Jaguar V8 5.0 mystery missfire!

[classicvanquish]

Hi all,

Very confused by my latest project.

I bought an F Type R that was a none runner, an injector was seized in the LH head.

I ended up stripping both heads, doing valve stem seals and checking over the RH head and replacing the LH.

Engine rebuilt and running fine, booked for a MOT and then things have got weird...here is the sequence of events.

Drove to Tesco, filed up with normal unleaded.
200m later while sat in traffic car suddenly starts to missfire and white smoke is pouring out of back. I nursed the car home and have done the following.

Read codes, "invalid data received from gateway A", missfire on cylinder 3&4, fuel pressure too low

I have done the following;

- Replaced plugs
- New coil packs
- New injectors
- measured compression ratio, all 140psi on RH bank, all 115psi on LH bank
- Continuity check on injector and coil wiring
- ran without RH cat
- no coolant or oil usage
- new battery
- checked fuel request compared to actual pressure and they are very close

Error codes are still there but seems to run for a couple of seconds and then goes back to misfiring again.

Any ideas?!

Edited by classicvanquish on Monday 4th May 04:28

[E-bmw]

classicvanquish said:

I ended up stripping both heads, doing valve stem seals and checking over the RH head and replacing the LH.

Engine rebuilt and running fine, booked for a MOT and then things have got weird...here is the sequence of events.

Drove to Tesco, filed up with normal unleaded.
200m later while sat in traffic car suddenly starts to missfire and white smoke is pouring out of back. I nursed the car home and have done the following.

Read codes, "invalid data received from gateway A", missfire on cylinder 3&4, fuel pressure too low

- measured compression ratio, all 140psi on RH bank, all 115psi on LH bank

My guess is there is a problem with the LH head.

White "smoke" out of a NA petrol engine is steam.

Don't know on this car/engine but is it possible to isolate left exhaust from right to see if the "white smoke" is coming from the left bank?

Best bet if it were mine would be to remove the head again & get out the "fine tooth comb" to search for possible issues.

ETA.
Obviously you could potentially get a pressure test done and borescope inspection first before stripping down.

Edited by E-bmw on Monday 4th May 09:20

[stevieturbo]

classicvanquish said:

Read codes, "invalid data received from gateway A", missfire on cylinder 3&4, fuel pressure too low

I have done the following;

- Replaced plugs
- New coil packs
- New injectors
- measured compression ratio, all 140psi on RH bank, all 115psi on LH bank
- Continuity check on injector and coil wiring
- ran without RH cat
- no coolant or oil usage
- new battery
- checked fuel request compared to actual pressure and they are very close

Error codes are still there but seems to run for a couple of seconds and then goes back to misfiring again.

Any ideas?!

So did you do anything relating to the codes ? Did you check fuel pressure ? Have you checked comms with all the modules on the car ? Any data suspect ?

Do you know any history behind the non runner aspect as to why it was sold ?

First thing instead of a parts cannon, is get talking to the car and see what is going on with this "gateway". Could be a bad module, or could be damaged wiring somewhere.

[classicvanquish]

Thanks for the thoughts.

In terms of fuel pressure I looked in icarsoft and request fuel and fuel rail pressure were almost identical, so have assumed fuel pumps are ok.

Only wiring I have checked is continuity from ECU to injectors and coils.

Plan on doing a leak down test either later today or next weekend.

Guy that sold it said it was running fine until he had a missfire that was diagnosed as a faulty injector

This year of F Type is prone to injector failure mostly due to the air exits on the bonnet being above the injectors which drip water and corroded everything in sight so I am inclined to believe him to be honest.

Also I had it running sweet, until it wasn't!

[E-bmw]

classicvanquish said:

Also I had it running sweet, until it wasn't!

That happenned with a V40 I had a couple of years ago, it went perfectly until it didn't....... Replacement engine later it ran perfect again.

[E-bmw]

Addendum to original reply.

Are you 100% certain you did all stages of the torqueing correctly on the left bank?

[E-bmw]

classicvanquish said:

This year of F Type is prone to injector failure mostly due to the air exits on the bonnet being above the injectors which drip water and corroded everything in sight so I am inclined to believe him to be honest.

Going back to Stevie's reply (good advice as always) is it not possible that if the wiring at the injectors has been subject to multiple floods that the wiring/plugs have been damaged/rusted/shorted in that area?

Surely, that could cause comms issues etc.

[classicvanquish]

100% certain I did the correct torque across both heads, I took my time and followed the workshop manual to the letter, I was aware of the consequences of rushing!

Could the wiring be corroded? Yes maybe, I checked the continuity across the wiring in that area and all seemed ok is all.

I haven't checked Comms across the various control units and certainly the ECU could have an issue but the car runs ok for a few seconds, and then only 2 cylinders on sesperate banks have an issue.

I think I need to do a leak down to confirm the mechanical build is ok and spend some time on icarsoft I guess?

Edited by classicvanquish on Monday 4th May 11:40

[Ted Maul]

classicvanquish said:

100% certain I did the correct torque across both heads, I took my time and followed the workshop manual to the letter, I was aware of the consequences of rushing!

The consequence of me rushing a torque setting was a £13k repair bill.

[Megaflow]

How are the cylinders numbered? Older engines would have odd's on one bank and evens on the other, more modern engines seem to have 1-4 down one bank and 5-8 down the other.

[Hereward]

Assume this is the AJ133 engine?

The nearside bank is 2,4,6,8
Offside bank is 1,3,5,7

Did you fit decent replacement injectors? I think they should be Bosch 0261500298.

Did you fit new injector locating clamps onto the top of each injector before refitting the fuel rails?

[Megaflow]

Hereward said:

Assume this is the AJ133 engine?

The nearside bank is 2,4,6,8
Offside bank is 1,3,5,7

Did you fit decent replacement injectors? I think they should be Bosch 0261500298.

Did you fit new injector locating clamps onto the top of each injector before refitting the fuel rails?

Interesting, that would seem to suggest the problem cannot be common to the cylinder head.

I saw a video on RE Performance channel where a Gallardo had a two cylinder misfire and it turned out to be a faulty injector and that one injector was dragging the driver in the ECM down to 0V, so it that it had a fault on the other as well.

[E-bmw]

Megaflow said:

Hereward said:

Assume this is the AJ133 engine?

The nearside bank is 2,4,6,8
Offside bank is 1,3,5,7

Did you fit decent replacement injectors? I think they should be Bosch 0261500298.

Did you fit new injector locating clamps onto the top of each injector before refitting the fuel rails?

Interesting, that would seem to suggest the problem cannot be common to the cylinder head.

I saw a video on RE Performance channel where a Gallardo had a two cylinder misfire and it turned out to be a faulty injector and that one injector was dragging the driver in the ECM down to 0V, so it that it had a fault on the other as well.

That would seem to tie in with there being 2 issues at play here, which seems to tie in with what the OP is saying.

Problem 1. Comms/injector/misfire.

Problem 2. Low compression across full left bank.

Obviously 2 could also be contributing to 1 for the misfire, but likely 2 separate issues.

Just my 2p.

[BOR]

There's no chance that the Tesco fuel was contaminated with water?

Might be worth drawing off some fuel via the fuel rail to check.

[E-bmw]

BOR said:

There's no chance that the Tesco fuel was contaminated with water?

Might be worth drawing off some fuel via the fuel rail to check.

Just tell me how that stops ECU communications or reduces one bank of compression?

[Krikkit]

This is a very odd one for a few reasons...

Compression test - wet or dry? I assume cold? Such a big difference between sides (and being relatively low for both) suggests something odd. I'd have expected about 180psi for a good test on a 9.5:1 engine. Was it done at full throttle opening? Either way I'd disregard these results and re-do it if you think it's a mechanical issue.

But the communication error suggests something in the loom is incorrect, either from a pinched/damaged wire or as noted an injector fault. I'd be probing everything in the loom as far as you can.

[Megaflow]

Krikkit said:

This is a very odd one for a few reasons...

Compression test - wet or dry? I assume cold? Such a big difference between sides (and being relatively low for both) suggests something odd. I'd have expected about 180psi for a good test on a 9.5:1 engine. Was it done at full throttle opening? Either way I'd disregard these results and re-do it if you think it's a mechanical issue.

But the communication error suggests something in the loom is incorrect, either from a pinched/damaged wire or as noted an injector fault. I'd be probing everything in the loom as far as you can.

I thought the compression test was a little odd as well, but concluded the fact the misfire is across both banks is a much bigger issue at this stage of diagnosis.

[classicvanquish]

Thanks for the input, not replied as away with work!

All injectors and coils were Bosch, all injectors had new clamps.

Compression test was dry, can't remember if I did it with an open or closed throttle tbh.

Agree the test results seem low but thought the consistency was more important than an ultimate number?

I'm not sure if I mentioned but I took the RH cat off thinking there might be some damage but looks absolutely fine. I ran it without the cat on just in the name of discovery and just before the misfire error there was a U0477-00 error code, invalid data received from gateway A.

This error code was present when I ran it before but I disregarded it thinking it was a by product of the misfire but now thinking it might be the other way round?

A bit of research suggests it could be the start stop battery but don't think it would cause this?

Edited by classicvanquish on Friday 8th May 19:20

[Megaflow]

I’d be surprised if is was the auxiliary battery, but modern cars are very sensitive to battery voltage, so who knows. It might be an idea to charge it off the car just to rule it out.

[Krikkit]

Two suggestions tie into that code - aux battery dead, and HPFP connectors crossed over. I'd check both and see what you get.

What scan tool are you using OP?

Megaflow said:

I thought the compression test was a little odd as well, but concluded the fact the misfire is across both banks is a much bigger issue at this stage of diagnosis.

Agreed, but it's odd.