fuel pump power 85 wedge federal
Discussion
Looks like I just found another problem and it may be the reason the engine seems "flat". At idle I removed each of the plug wires to see if the engine was hitting on all cylinders and no response at number one. The other five all gave the expected drop in idle speed and slight roughness. Pulled the plug and it was carbon black, bead blasted it with no improvement and it sparks nicely when removed and set on the plenum. Next guess is the injector is plugged. I have been running a high concentration of Sea Foam in the fuel and I had hoped it would help the injectors after the four years of not being run.
I assume removing the plenum will make all the injectors reachable. Any suggestions on cleaning them without professional help? Can compressed air be blown through them without damage? Once removed how do you tell if they are defective? Can the injector seals be reused?
I would appreciate any suggestions!
John
I assume removing the plenum will make all the injectors reachable. Any suggestions on cleaning them without professional help? Can compressed air be blown through them without damage? Once removed how do you tell if they are defective? Can the injector seals be reused?
I would appreciate any suggestions!
John
Just before you start taking injection apart -
Spark plugs can fail such that they spark in air, outside engine, but fail when fitted, as pressure is a lot higher.
It's only a 2 minute job to swop 2 plugs over, or use a new one, just to make sure.... The lead can fail too, but you can normally hear a 'tick'
From your description, the plug would be wet (and smell of fuel) if you were getting fuel, so it probably is injector or pipe to it..etc.
Injectors
Recommendations are not to try to clean injectors - but I have seen the 'tap' trick work on mechanical injectors.
1. Take injector out.
2. lift metering flap a little. Wwedge a small piece of something, like a small piece of wood, biro, pencil, folded over paper, under flap so you get some fuel flow.
3. Bridge relay - so pump works.
(3a. Check if there's any dribble or anything from injector.)
4. Try tapping injector body with spanner - not really hard, but sharp taps, to try to get any muck dislodged....
5. Don't run pump for very long, as you are injecting petrol into other cylinders.
Believe it or not, I have seen this actually work !!
If you can't get any flow, then it's a professional job, or a new injector.
I guess with care, you could loosen injector to check there's fuel in the supply pipe, but petrol tends to spray everywhere, so careful !!
NB. I think you may be able to get no 1 injector out without removing the plenum - there is a small bolt holding the plate which locks the injector in. if you can get that off, injector should just pull out.
Spark plugs can fail such that they spark in air, outside engine, but fail when fitted, as pressure is a lot higher.
It's only a 2 minute job to swop 2 plugs over, or use a new one, just to make sure.... The lead can fail too, but you can normally hear a 'tick'
From your description, the plug would be wet (and smell of fuel) if you were getting fuel, so it probably is injector or pipe to it..etc.
Injectors
Recommendations are not to try to clean injectors - but I have seen the 'tap' trick work on mechanical injectors.
1. Take injector out.
2. lift metering flap a little. Wwedge a small piece of something, like a small piece of wood, biro, pencil, folded over paper, under flap so you get some fuel flow.
3. Bridge relay - so pump works.
(3a. Check if there's any dribble or anything from injector.)
4. Try tapping injector body with spanner - not really hard, but sharp taps, to try to get any muck dislodged....
5. Don't run pump for very long, as you are injecting petrol into other cylinders.
Believe it or not, I have seen this actually work !!
If you can't get any flow, then it's a professional job, or a new injector.
I guess with care, you could loosen injector to check there's fuel in the supply pipe, but petrol tends to spray everywhere, so careful !!
NB. I think you may be able to get no 1 injector out without removing the plenum - there is a small bolt holding the plate which locks the injector in. if you can get that off, injector should just pull out.
Edited by RCK974X on Saturday 24th January 02:01
Edited by RCK974X on Saturday 24th January 02:03
I was pretty careful with checking the spark in number one. Plug was dry black and had been ten miles from new. I think I will go ahead and remove the plenum. With it off it should be easy to compare number one injector with any of the others.
Thanks for check out process, probably a couple of day till I get to it.
Cheers,
John
Thanks for check out process, probably a couple of day till I get to it.
Cheers,
John
RCK974X said:
NB. I think you may be able to get no 1 injector out without removing the plenum - there is a small bolt holding the plate which locks the injector in. if you can get that off, injector should just pull out.
I managed to get to all the injectors without removing the plenum..Admittedly it is easier with it off....
jforrester42 said:
I was pretty careful with checking the spark in number one. Plug was dry black and had been ten miles from new. I think I will go ahead and remove the plenum. With it off it should be easy to compare number one injector with any of the others.
Thanks for check out process, probably a couple of day till I get to it.
Cheers,
John
No worries, just that I've learned that sometimes it was an obvious problem that I missed, so passing around my pain !!Thanks for check out process, probably a couple of day till I get to it.
Cheers,
John
Dry plug after drive...Yep - something injection.
I know with electronic injectors, the cleaners reverse flush, but you can't do that with a mechanical injector as it simply has a spring loaded valve head. I think that's why they use the ultrasonic ones (which basically shake the crap out).
Good news, bad news!! I will back up minute. Last week I commented the engine felt flat and after about two miles quit like it was out of fuel, restarted and repeated the symptoms. I replaced the filter I had added between the swirl pot and the fuel pump. I cut open the old one and there was powder crud inside but I do not know if it was enough to stop the fuel flow. I also drained the tanks and put in new fuel and Sea Foam Conditioner. Engine started right up with the new filter. That is when I tested each spark plug wire and found that number one cylinder was not firing.
Today I removed the plenum and number one injector I soaked it in Sea Foam, forced some into the injector by tapping on it. I then tried compressed air and after a couple of cycles of sea foam treatment the injector seemed to open up and had a good spray. I hooked it to its fuel line and ran the fuel pump and it sprayed when I lifted the metering flap. I (we) reassembled the plenum and the engine fired right up and was running on all six cylinders! I let it get full temp and adjusted the air bleed. The engine was very smooth and ran better than it ever had since I have owned it! Then a test drive, engine pulled so much better with all six cylinders hitting. Ran it up through the gears a number of times with good results THEN after about two miles the engine sputtered and almost quit. I was within sight of my shop and with some effort got it into my driveway. Engine then quit and after some cranking would start and quit again. after about six or eight of these cycles I got it parked in the shop. I was concerned the new fuel filter was already plugged so I opened the fitting where the fuel enters the metering unit and a gush of fuel came out. I also cracked open one of the lines to one of the injectors and again a good squirt. I checked for spark and it seemed ok. So I do not know what is causing the engine to quit. The engine now starts and runs in the garage but no more test drives!!
Speculation on my part: is it possible the metering unit is sticking sometimes? Help! I am out of ideas!!
Cheers and thanks for any thoughts,
John
Today I removed the plenum and number one injector I soaked it in Sea Foam, forced some into the injector by tapping on it. I then tried compressed air and after a couple of cycles of sea foam treatment the injector seemed to open up and had a good spray. I hooked it to its fuel line and ran the fuel pump and it sprayed when I lifted the metering flap. I (we) reassembled the plenum and the engine fired right up and was running on all six cylinders! I let it get full temp and adjusted the air bleed. The engine was very smooth and ran better than it ever had since I have owned it! Then a test drive, engine pulled so much better with all six cylinders hitting. Ran it up through the gears a number of times with good results THEN after about two miles the engine sputtered and almost quit. I was within sight of my shop and with some effort got it into my driveway. Engine then quit and after some cranking would start and quit again. after about six or eight of these cycles I got it parked in the shop. I was concerned the new fuel filter was already plugged so I opened the fitting where the fuel enters the metering unit and a gush of fuel came out. I also cracked open one of the lines to one of the injectors and again a good squirt. I checked for spark and it seemed ok. So I do not know what is causing the engine to quit. The engine now starts and runs in the garage but no more test drives!!
Speculation on my part: is it possible the metering unit is sticking sometimes? Help! I am out of ideas!!
Cheers and thanks for any thoughts,
John
Hi John..It is possible by the sound of it that the "Crud" has managed to get drawn up and into the accumulator..Metering head..WUR and injectors..All the running problems i ever had with mine were "Crud" in the system related....Have you checked all the injectors for spray pattern?....Have you touched the metering head adjustment screw?...Is fuel coming out of the fuel return on the metering head..You can try clamping it briefly to see if it will run, This will determine if the metering head is faulty...If the accumulator has failed then the fuel pressure will be lost, Although this normally only affects hot starting...It can be clamped off and by-passed...You can test it by clamping off the feed to the bulkhead filter and remove the breather on the back of the diaphragm, Activate the fuel pump briefly and if fuel comes out then it is "Kaputt" as it should only be air....Has the metering head been rebuilt?...The fine mesh inside can get blocked and the plunger can stick..There might also be something electrical fitted to the US cars that could hinder the fuel although I'm not familiar with those components...Ziga
I did have a problem in another vehicle which sounds quite like yours. Basically, there was a crud build up in the pipe from the fuel tank to the main pump. Driving on light throttle it was fine, but on acceleration the pump got starved of fuel supply, and the engine would stall. After being really hard to start, it would be Ok for a while, and then repeat the symptoms.
I also had a wedge issue with main fuel filter (in engine compartment) being partly gummed up, but it was different symptoms where engine would just go 'flat' on heavy acceleration, but did not stall. New filter fixed that, and I too got a pile of what looked like sand out of the old filter.
I also had a wiring fault which caused engine to run extremely rich a long time ago - the electrically heated warm up unit wasn't getting power, so kept the enrichment engaged, flooding the engine.
So it probably is crud somewhere, especially after putting cleaner in the system....I can only advise going through pipework, and also checking things like metering head plunger is free (be VERY careful if you take it out, the manufacturing clearances are TINY !!)
I feel your pain...... but keep going, you will find it, and then it will be all worth it next time you drive...
I also had a wedge issue with main fuel filter (in engine compartment) being partly gummed up, but it was different symptoms where engine would just go 'flat' on heavy acceleration, but did not stall. New filter fixed that, and I too got a pile of what looked like sand out of the old filter.
I also had a wiring fault which caused engine to run extremely rich a long time ago - the electrically heated warm up unit wasn't getting power, so kept the enrichment engaged, flooding the engine.
So it probably is crud somewhere, especially after putting cleaner in the system....I can only advise going through pipework, and also checking things like metering head plunger is free (be VERY careful if you take it out, the manufacturing clearances are TINY !!)
I feel your pain...... but keep going, you will find it, and then it will be all worth it next time you drive...
Sorry I'm not paying attention:....You have replaced the accumulator so thats okay..You had the metering unit rebuilt so that should be fine..The WUR...Which sits in front of the LH rocker cover just right of the water pump..It has two plastic fuel lines going to it..One is feed and the other return..This is a fuel regulator as well as the metering unit, If the only two components you haven't replaced are the injectors or the WUR then it could be either...I wouldn't of used sea foam despite its claims..The injectors are best cleaned professionally or replaced...I think you might be lucky to find a set..I have a set but they were blocked with rust particles..They are probably rusted shut now so not worth cleaning...One of the lines are the return from the WUR and you can just open the banjo fitting until it seeps although this is not a good way if you are looking for crud..
Lets summarise...
A. You cleaned the fuel tanks and swirl pot and changed the fuel filters....
A. You replaced the accumulator.
A. You had the metering unit rebuilt.
Q. Did you change all the fuel hose from the tanks to the metering unit?
If the answer to this is no then there is a possibility that after all your efforts you may of had contaminated fuel hose which has now got into the system again..The bonus being the metering units tiny screen mesh filter is new and should prevent crud from entering the main body..Also if the bulkhead filter was changed then there is only the contamination from the filter to the metering unit...It could just be the injectors......Ziga
Lets summarise...
A. You cleaned the fuel tanks and swirl pot and changed the fuel filters....
A. You replaced the accumulator.
A. You had the metering unit rebuilt.
Q. Did you change all the fuel hose from the tanks to the metering unit?
If the answer to this is no then there is a possibility that after all your efforts you may of had contaminated fuel hose which has now got into the system again..The bonus being the metering units tiny screen mesh filter is new and should prevent crud from entering the main body..Also if the bulkhead filter was changed then there is only the contamination from the filter to the metering unit...It could just be the injectors......Ziga
Thanks to both of you for your comments and advice. I'll do a recap of what I have done over the last few months. First I drained about a gallon or two of smelly fuel from tanks. Removed the swirl pot and cleaned it and installed new hoses from the tanks to the pot. Began adding a gallon or two of fresh fuel and Sea Foam, letting it sit overnight, drained it and repeated this six or eight times. Drained fuel never seemed to have crud in it but was discolored. Replaced frozen fuel pump and added a filter between it and the swirl pot. Replaced fuel accumulator which leaked. Blew compressed air through the fuel line from pump to bulkhead filter, and compressed air from return line back to tanks. Bypassed power to pump and ran fuel into catch can at bulkhead filter input. Fuel looked good with no "visible" crud. Replaced bulkhead filter and attempted to start engine, no go with occasional "put put" from engine. This is when I discovered there was no compression in two or three cylinders. Removed valve covers and adjusted valve clearance. There was no gap in some of the valves. Ran compression test again and all good. Added new spark plugs. Still no go. Sent off metering unit AND warm up regulator for rebuild. Removed air bypass, cleaned and tested it, ok. Re-installed metering unit, WOR,and air filter, engine fired right up! Engine seemed to run good at idle with a little hesitation when blip-ping the throttle. Short test drive and engine seemed very flat but having never having driven a Wedge did not know what to expect. Second test drive still "flat" and after about two miles stalled but was able to get home. Removed the filter at the swirl pot and drained the tanks, some powder crud in catch can and replaced with new filter. Cut open old filter and found some crud in it but probably not enough to stop all the fuel flow. Sorry to say with all of the changing of the filter I never checked the fuel flow to the bulkhead filter. At this point I checked the spark at each cylinder and found number one was dead though it had good spark. Yesterday I removed the plenum and the number one fuel injector which appeared to be plugged. I soaked it in Sea Foam and "tapped" it, with compressed air it appeared to open. I connected it to its fuel line, bypassed the pump, opened the metering flap and it sprayed a cloud of fuel. Put everything back together and the engine seemed to run in the shop better than ever and cylinder 1 was now active. Went for a test drive and a vast improvement in performance. Ran the car up through the gears a few times and had a smile on my face! THEN it stalled again shnxxentynxjbjer! Almost did not make it back to the shop with frequent stalling and painful restarts. In the shop I opened the fitting at the metering unit and a gush of fuel sprayed out. Opened a fitting to one of the cylinders on the metering unit and it also sprayed out. Gave up and locked the shop!! Went out to the shop today and it fired right up and ran smooth at idle, no test drive.
Sorry for the looooong dissertation. Just documents my efforts and frustration. You guys have been a great help and I hope tomorrow to try some of your latest suggestions.
Thanks as always!!
John
Sorry for the looooong dissertation. Just documents my efforts and frustration. You guys have been a great help and I hope tomorrow to try some of your latest suggestions.
Thanks as always!!
John
Hi mate...I do recall having the same symptoms as you, Especially with the No.1 cylinder down..I drove to my first Wedgefest on 5 cylinders and went on the rolling road and got 107bhp...Although i redeemed myself the following year with just over 200bhp...
Unfortunately the cologne isn't known for its performance but a good engine has good power, There is no low down torque but more of a gradual band across the rev range.
After i had replaced ALL the fuel system components on Delilah she still used to cut out and run bad...Then i was lucky enough to obtain some brand new injectors...It was the icing on the cake!...So i really hope this is your issue as it is most certainly a "HF"...The best part is when you said it made you smile...Hopefully more of that is on the menu....
Steve at KMI petrol injection might be worth an email..You can tell him that i recommended you...Not sure if he still stocks the injectors might might be able to point you in the right direction...I believe they are the same as the Taunus V4/V6
http://www.google.co.uk/url?sa=t&rct=j&q=&...
It also seems that Burton power have them...
http://www.burtonpower.com/parts-by-brand/brands-a...
Cheers...Ziga
Unfortunately the cologne isn't known for its performance but a good engine has good power, There is no low down torque but more of a gradual band across the rev range.
After i had replaced ALL the fuel system components on Delilah she still used to cut out and run bad...Then i was lucky enough to obtain some brand new injectors...It was the icing on the cake!...So i really hope this is your issue as it is most certainly a "HF"...The best part is when you said it made you smile...Hopefully more of that is on the menu....
Steve at KMI petrol injection might be worth an email..You can tell him that i recommended you...Not sure if he still stocks the injectors might might be able to point you in the right direction...I believe they are the same as the Taunus V4/V6
http://www.google.co.uk/url?sa=t&rct=j&q=&...
It also seems that Burton power have them...
http://www.burtonpower.com/parts-by-brand/brands-a...
Cheers...Ziga
Does the wedge have a strainer in the fuel tank swirl pot? If so, does yours? If you have a rusty tank then a strainer will stay clear for much longer than an inline filter because it is getting a good wash all the time. I tried a couple of inline filters on my current S before caving in and ordering strainers from England. If it's the same as the S, I might have a spare State-side, if that's where you are.
The large filter should prevent any crud from getting into the metering unit, etc. the fact that you had pressure there is one thing, but if there's not enough flow due to your inline filter, the engine will die.
The large filter should prevent any crud from getting into the metering unit, etc. the fact that you had pressure there is one thing, but if there's not enough flow due to your inline filter, the engine will die.
Zig,
Am I missing something about how the injectors work? To my knowledge they create a spray/cloud and contain a valve that prevents fuel from dripping into the intake when the engine is not running. All seems pretty simple but "fine" engineering for proper function. What I don't get is how with the engine running great and at the next press of the throttle it quits/gasps/etc. Would not all of the injectors have to malfunction at the same time to cause the engine to quit. Sorry if I am missing something! Both times the engine quit it was at a quick full throttle and then the feeling you get when a car runs out of fuel. Another note, the car has a"full throttle" vacuum actuated switch. When I got the car it was disconnected and the vacuum port plugged. I have reconnected it but do not know if it has any effect, good or bad. There is no mention of it in the Wedge bible so I have no idea what it actually does. I'll try disconnecting it for the next test drive. I think it was disconnected on my first failed drive. The car does have some sort of an ECU since it has an O2 sensor and a pressure regulator modulator. The cat converter has been "gutted". I think the claim for this "Federal" car was 145 hp.
David,
I do not know is there is a screen in the swirl pot. It is an aluminum can with the two in and one out half inch id fitting tubes. I cleaned it out with lacquer thinner and compressed air and it seemed to be ok. When I disconnect the outlet fuel pours out at a fast rate. New fuel lines from the tanks to the pot and onto the fuel pump. All the other lines are the originals. Yes, I live in north east Oklahoma.
Cheers to all, I'll keep trying!
John
Am I missing something about how the injectors work? To my knowledge they create a spray/cloud and contain a valve that prevents fuel from dripping into the intake when the engine is not running. All seems pretty simple but "fine" engineering for proper function. What I don't get is how with the engine running great and at the next press of the throttle it quits/gasps/etc. Would not all of the injectors have to malfunction at the same time to cause the engine to quit. Sorry if I am missing something! Both times the engine quit it was at a quick full throttle and then the feeling you get when a car runs out of fuel. Another note, the car has a"full throttle" vacuum actuated switch. When I got the car it was disconnected and the vacuum port plugged. I have reconnected it but do not know if it has any effect, good or bad. There is no mention of it in the Wedge bible so I have no idea what it actually does. I'll try disconnecting it for the next test drive. I think it was disconnected on my first failed drive. The car does have some sort of an ECU since it has an O2 sensor and a pressure regulator modulator. The cat converter has been "gutted". I think the claim for this "Federal" car was 145 hp.
David,
I do not know is there is a screen in the swirl pot. It is an aluminum can with the two in and one out half inch id fitting tubes. I cleaned it out with lacquer thinner and compressed air and it seemed to be ok. When I disconnect the outlet fuel pours out at a fast rate. New fuel lines from the tanks to the pot and onto the fuel pump. All the other lines are the originals. Yes, I live in north east Oklahoma.
Cheers to all, I'll keep trying!
John
When you say you adjusted the air blend, do you mean the large screw on the by pass (gives airflow when throttle closed.
Or do you mean the idle mixture on the Fuel distributor. (I hope not)
If it was this, return it to its factoery setting and approach the fault with an open mind.
The facts appear to be starts and runs from cold, but unwilling to start when hot after dying.
So logically, first list cold start components that change charecteristics as the engine heats.
7th injector and thermotime switch can be eliminated because they only affect the running for a very short time.
Leaving AAD and WUR and possibly the frequency valve, and of course a cooked coil. (If you have a permanent 12v on a coil that is expecting the ballest to be in circuit once key is released.)
If this is the case...don't frig about with wiring just stick any 12v coil on it and test.
Or do you mean the idle mixture on the Fuel distributor. (I hope not)
If it was this, return it to its factoery setting and approach the fault with an open mind.
The facts appear to be starts and runs from cold, but unwilling to start when hot after dying.
So logically, first list cold start components that change charecteristics as the engine heats.
7th injector and thermotime switch can be eliminated because they only affect the running for a very short time.
Leaving AAD and WUR and possibly the frequency valve, and of course a cooked coil. (If you have a permanent 12v on a coil that is expecting the ballest to be in circuit once key is released.)
If this is the case...don't frig about with wiring just stick any 12v coil on it and test.
Hi John...Well im not sure then...If all the injectors are okay then it could be an electrical sensor or something...As i said I'm not familiar with the US cars..Is the fuel filter on the pre or post pump side...Pre would be a normal inline filter but the post filter should be high pressure..As mentioned it could be a factor...Sorry if its been covered but hopefully you are 99.9% of being able to drive it..Smiling...I know that when i had completed my 280i TVR journey she was a very reliable car..And hopefully still is ..Where ever you are Delilah...
For info, not sure if it's any use....
The injectors are designed to spray fuel constantly, and deliver a fine atomised mist over a wide range of flow. Generally if worn, they tend to drip or not atomise properly, and this is far more likely to happen at low flow, or in other words, light throttle and idle. So if it runs smoothly at idle, the injectors are probably within spec. NB. this is totally different to 'pulsed' EFi systems, where the injector is also a solenoid valve.
YES, the K series DOES inject fuel ALL THE TIME. (just clearing up any confusion - I've had this argument with so called 'experts' more then a few times).
Symptoms - best guesses
Did the engine suddenly cut out completely ? Like BANG - dead ? Cos this seems electrical to me, not fuel.
Unless the fuel system gets totally blocked, the engine tends to go flat and misfire before dying when starved of fuel, but with injection systems it can be quite fast, not like carbs.
Unfortunately non of us Brits (ex-pats) has experience of the US extras, which is another unknown.
What if EGO is disconnected - box must have a failsafe setting ? May be worth a try too...
Can only think to investigate when it dies, at the side of the road - check fuel, sparks etc. Not very helpful I know....
The injectors are designed to spray fuel constantly, and deliver a fine atomised mist over a wide range of flow. Generally if worn, they tend to drip or not atomise properly, and this is far more likely to happen at low flow, or in other words, light throttle and idle. So if it runs smoothly at idle, the injectors are probably within spec. NB. this is totally different to 'pulsed' EFi systems, where the injector is also a solenoid valve.
YES, the K series DOES inject fuel ALL THE TIME. (just clearing up any confusion - I've had this argument with so called 'experts' more then a few times).
Symptoms - best guesses
Did the engine suddenly cut out completely ? Like BANG - dead ? Cos this seems electrical to me, not fuel.
Unless the fuel system gets totally blocked, the engine tends to go flat and misfire before dying when starved of fuel, but with injection systems it can be quite fast, not like carbs.
Unfortunately non of us Brits (ex-pats) has experience of the US extras, which is another unknown.
What if EGO is disconnected - box must have a failsafe setting ? May be worth a try too...
Can only think to investigate when it dies, at the side of the road - check fuel, sparks etc. Not very helpful I know....
A cooked coil is "uncomfortable to hold"
With regard to the O2 sensor ECU etc.
The car runs open loop til it is hot. That means the frequency valve will pulse at a rich setting (50/50 I think.
Once the O2 sensor gets hot the ECU send a signal to frequency valve to lean out the mixture (changes the pulse rate to something like 80/20 70/30.
Full throttle does affect the pulse rate of the Frequency valve, I'm not sure which way but I would guess it would send it back to open loop.
The ECU and O2 sensor do not know you have no cat.
As it stalled/stopped on full throttle, try pulling the wire off the O2 sensor this will stop the car going closed loop, the ECU should then maintain the richer of the two settings.
A bit like limp mode in modern a car, but much more drivable
Wrther the full throttle thing still has effect in open loop I don't know, but I'll try to find out. Pretty sure it doesn't but will check.
With regard to the O2 sensor ECU etc.
The car runs open loop til it is hot. That means the frequency valve will pulse at a rich setting (50/50 I think.
Once the O2 sensor gets hot the ECU send a signal to frequency valve to lean out the mixture (changes the pulse rate to something like 80/20 70/30.
Full throttle does affect the pulse rate of the Frequency valve, I'm not sure which way but I would guess it would send it back to open loop.
The ECU and O2 sensor do not know you have no cat.
As it stalled/stopped on full throttle, try pulling the wire off the O2 sensor this will stop the car going closed loop, the ECU should then maintain the richer of the two settings.
A bit like limp mode in modern a car, but much more drivable
Wrther the full throttle thing still has effect in open loop I don't know, but I'll try to find out. Pretty sure it doesn't but will check.
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