Engine Stalling on '90 SE
Discussion
My '90 SE is sometimes stalling during quick acceleration, and sometimes during normal cruising. The check engine light flashes on and the car looses power then everything comes back on (all in a fraction of a second). On occaision, the car simply will not start. After several tries, it will begin working normally again. Since it does not happen all the time, it is very difficult to troubleshoot. Does anyone have any experience with this? Thanks -ryan
Ryan, I also have a 90SE and experienced the same symptoms. You need to look at the IAC motor and/or the TPS sensor. IAC allows air to bypass the throttle plates at idle and can sieze up after years of high heat. I found an exact replacement at the GM dealer for a 2.8L Fiero .Fit & Worked perfectly, TPS is the Throttle Position Sensor and is very sensitive. A voltage variation beyond the normal parameters will definitely affect idle and acceleration. TPS is a Lotus part only. Pull the IAC and gently try to push the plunger in. It should slide in fairly easily , if it is tight it probably is the trouble. Have you done a self diagnostic with the ALDL and engine light ?
Contact me if you have questions
Scott snbrowne4@sympatico.ca
Contact me if you have questions
Scott snbrowne4@sympatico.ca
wonderman: I have tested the ECU, no errors were logged. I have suspected the O2 sensor for a couple of reasons: 1 engine is backfiring on occaision, 2 engines can backfire because of too much fuel, which could also cause a stall. I have replaced the O2 sensor from AutoZone, the backfiring has gone away for now, and the stalls seem to have also gone away, but I will need to drive the car more to be certain.
Hi Ryan,
If you are not logging a check engine code, there is a very good chance that the problem is caused by a bad electrical connection. Check the ground cables that attach to the engine from the battery, as well as any other connections related to the ECM, such as fuseholders, fuses, etc.
Cheers,
Sanj
If you are not logging a check engine code, there is a very good chance that the problem is caused by a bad electrical connection. Check the ground cables that attach to the engine from the battery, as well as any other connections related to the ECM, such as fuseholders, fuses, etc.
Cheers,
Sanj
Calvin,
I have replaced the ECU in my car, I have yet to determine if this has fixed my engine starting problem, but time will tell. I am still having stalling problems during normal cruising and sometimes during bumps, this almost has to be an electrical connection somewhere. You had mentioned that the coil packs could be going out, so I would like to test this further. Pardon my ignorance, but this is the part that generates the spark for the plugs? I hope this is a commonly available part (by the way, I am using the NGK plugs, they are new, the fuel filter is new also). Another response indicated that I should check the IAC valve. Is this part easy to get to? Where is it located? I need to get the parts list for this car.
Thanks Again for all your help. -ryan
I have replaced the ECU in my car, I have yet to determine if this has fixed my engine starting problem, but time will tell. I am still having stalling problems during normal cruising and sometimes during bumps, this almost has to be an electrical connection somewhere. You had mentioned that the coil packs could be going out, so I would like to test this further. Pardon my ignorance, but this is the part that generates the spark for the plugs? I hope this is a commonly available part (by the way, I am using the NGK plugs, they are new, the fuel filter is new also). Another response indicated that I should check the IAC valve. Is this part easy to get to? Where is it located? I need to get the parts list for this car.
Thanks Again for all your help. -ryan
Oh good, I see that Sanj is visiting, please check in often an offer your valuable advice as I am seeing a lot of 4 cyl. action here. I know when we chatted at LOG you prefered the way the list was formatted as this site's formatting is a little different. Still we could all use all the advice from the hardcore 4 cyl guys. Ryan, the coil packs have been known to go out they are what the plug wires are connected to. You have checked the obvious stuff like the plug wires themselves posibbly banging around when you hit bumps right? I'll check on the other possible items when I get home and look at parts manual. A lot of things you are checking I have not had to look into. Let's solve this problem of yours it will be a good learning experience for me. Also I have noticed that the wall of the trunk where the fuel cut off reset that hold items behind the hatch flexes a bit. There might be a connection there that might make an engine miss when you hit a bump.
Calvin
Calvin 90 SE
Calvin
Calvin 90 SE
Calvin,
I bypassed the fuel pump cut-off just to see if it was shorted out, that did not seem to be the problem. I have also opened each of the 8 relays in hopes of finding corrosion of the contacts, but they were all in new condition, in fact I would guess they been recently replaced.
I will check the coil packs as you suggested. The way the car behaves, it seems to happen so quick that it I keep thinking it is a spark plug miss of some sort. I will check into it today.
I bypassed the fuel pump cut-off just to see if it was shorted out, that did not seem to be the problem. I have also opened each of the 8 relays in hopes of finding corrosion of the contacts, but they were all in new condition, in fact I would guess they been recently replaced.
I will check the coil packs as you suggested. The way the car behaves, it seems to happen so quick that it I keep thinking it is a spark plug miss of some sort. I will check into it today.
I was thinking either that or something with an intermitant break. Sometimes when plug wire are old or bang against the block where the insulation is thin it can arc and cause a miss. Sometimes the carbon has gap when the wire flexes and opens up a spot momentarily. Other than that if something else is a miss when going over a bump I have his little rubber hammer like the doc use to check reflexes and while the engine is running I gently tap with the hammer on components to make the problem happen. Many times when I can not solve the problem I feel like tapping it a little more forcefully but I restrain myself.
Calvin
Calvin
Calvin
Calvin
Ryan:
Except for the dipstick, the IAC is the easiest part in the world to replace. It is (on mine anyway) right in back of the oil filler cap, below the fuel rail, about 3" from the timing belt. It is a black plastic oval shaped thing with wires on top. Unscrew two screws (those unusual types), pull it out, disconnect/reconnect the wire connection, done. A stock Lotus IAC is $ 100. The counter guy mentioned a GM part might work, but why risk it?
My car was idiling WAY too high, and this fixed it perfectly.
Except for the dipstick, the IAC is the easiest part in the world to replace. It is (on mine anyway) right in back of the oil filler cap, below the fuel rail, about 3" from the timing belt. It is a black plastic oval shaped thing with wires on top. Unscrew two screws (those unusual types), pull it out, disconnect/reconnect the wire connection, done. A stock Lotus IAC is $ 100. The counter guy mentioned a GM part might work, but why risk it?
My car was idiling WAY too high, and this fixed it perfectly.
Skerd, Calvin,
Thanks for the reponses. I will try both suggestions. I am currently battling a cooling system issue and hope to resolve all of this soon. I have to say, working on this car is a lot of fun, I am getting to know the engine components well. This may sound strage, but I am enjoying what others would perceive to be headaches. The troubleshooting process has always been a lot of fun. It seems my Lotus and I are a perfect fit for each other. -ryan
Thanks for the reponses. I will try both suggestions. I am currently battling a cooling system issue and hope to resolve all of this soon. I have to say, working on this car is a lot of fun, I am getting to know the engine components well. This may sound strage, but I am enjoying what others would perceive to be headaches. The troubleshooting process has always been a lot of fun. It seems my Lotus and I are a perfect fit for each other. -ryan
Calvin,
I did your "Tap Test" and found the problem. The fuse to the Fuel Pump was not making a good connection. Problem solved! However, a new and potentially dangerous problem has started. It seems my left rear brake tends to freeze on occaision, causing me to nearly loose control of the car. I won't chance it, going to buy new calipers for the rear. I nearly lost it twice. Thank god this car handles so well, I was able to regain control both times.
Ryan
I did your "Tap Test" and found the problem. The fuse to the Fuel Pump was not making a good connection. Problem solved! However, a new and potentially dangerous problem has started. It seems my left rear brake tends to freeze on occaision, causing me to nearly loose control of the car. I won't chance it, going to buy new calipers for the rear. I nearly lost it twice. Thank god this car handles so well, I was able to regain control both times.
Ryan
Ryan,
You would be suprised how many simple tricks of the trade there are concerning fixing a car like ours. I have run across many an old timer that does things like what we have done to fix a car. Sometimes those guys just know like sone type of 6th sense. Something all the fancy scopes and gagetry will not solve. Oh there is a time and place for them. But if you combine both ways you will be one awesome Lotus mechanic. You do not need to buy new calipers. What you need to do is go to the auto store and get some synthetic caliper grease to lube the piston or pot. Remove the pad and have someone very slowly push the brake pedal, but not too much and the piston will come out a bit. Smear a little grease lightly all over the exposed piston. I use a what is called a quik grip a pistol grip pump action vise to retract the piston into the caliper, you can also use a C clamp too but it will be slower. Pump the pedal again and repeat. Make sure all things that slide and move are lubed up (like floating pins of the calipers like the ones in the front brakes if doing them too). Sometimes the lube gets cooked off the brakes by sticking of the parking brake lever at the brakes so lube them too so they release smoothly. Do this and your car will be happy.
Calvin
You would be suprised how many simple tricks of the trade there are concerning fixing a car like ours. I have run across many an old timer that does things like what we have done to fix a car. Sometimes those guys just know like sone type of 6th sense. Something all the fancy scopes and gagetry will not solve. Oh there is a time and place for them. But if you combine both ways you will be one awesome Lotus mechanic. You do not need to buy new calipers. What you need to do is go to the auto store and get some synthetic caliper grease to lube the piston or pot. Remove the pad and have someone very slowly push the brake pedal, but not too much and the piston will come out a bit. Smear a little grease lightly all over the exposed piston. I use a what is called a quik grip a pistol grip pump action vise to retract the piston into the caliper, you can also use a C clamp too but it will be slower. Pump the pedal again and repeat. Make sure all things that slide and move are lubed up (like floating pins of the calipers like the ones in the front brakes if doing them too). Sometimes the lube gets cooked off the brakes by sticking of the parking brake lever at the brakes so lube them too so they release smoothly. Do this and your car will be happy.
Calvin
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