Technical Help! Poss fault with ECU

[millymoon]

Hi, I recently bought a 2001 1.9TD ELX 105 JTD Multipla cheaply which, I was advised, required only a new turbo. The turbo was duly replaced and ever since then virtually every part under the bonnet has been replaced and yet still the car has a problem going over 3000 revs. :bang: I have had two seperate mechanics to look at it and finally it appears the fault is either a ECU problem or a wiring problem, neither of which seems to be a cheap option. The problem appears to be that there is no vaccum to the turbo. The overboost solenoid was changed and we have checked that the wastegate works (in theory) so it seems the solenoid is not recieving a signal from the ECU. Before we send the ECU away for testing, could anyone please advise 1. What can be done to find out if the solenoid is receiving a signal from the ECU 2. What the voltage should be for testing the wires to the solenoid. 3. Is there any way to test the overboost valve. ANY HELP/THOUGHTS AT ALL would be very gratefully welcomed

 

[matt8772]

have you got a vacuum to the overboost solenoid?

 

[millymoon]

Hi, How would we be able to tell? we've carefully checked the pipes to and from the solenoid and they appear to be fine... is there another way?

 

[matt8772]

umm, this is from memory so it might not be 100pc accurate but it also might help.

pull off the supply pipe to the vac solenoid with the engine running and you should have a permanent vacuum to it.

best way to tell is to put your tongue over the end of it!

once youve reconnected it all and okayed the supply, disconnect the vacuum pipe to the turbo and see if you have a vacuum there too. it should plug in to the waste gate actuator, a large bell/cylindrical shaped component on the turbo.

if you have a vacuum here, plug the pipe back onto the actuator and get some one to rev the engine. this is the bit i cant really remember (and i have the missus yapping in the other ear ), but the vacuum either keeps the turbo waste gate shut, or opens it. so with someone revving the engine, check if the rod that comes out of the actuator is moving back and forth.

if it isnt either the vacuum diaphragm has gone in the actuator or the wastegate is a bit sticky, and hopefully all its gonna cost you is a can of penetrating spray!

difficult to think of anything else without actaully working on the car itself or having the required diag tools to hand.

 

[millymoon]

Thanks so much for this. You're an absolute STAR for helping. :worship:My ex is down tomorrow, so have roped him in to help. Will attempt this tomorrow and get back to you. Any advice you can offer is fantastic.

 

[matt8772]

no worries hope some of it might be of use difficult to remember it when you havent worked on one for a while!

one thing i forgot to put is if you havent got a vacuum to the turbo when you disconnect the pipe try getting someone to either give the vehicle a short sharp (but not excessive) burst on the throttle or hold the revs at about 2500 to 3000 and see if you get a vac then.

 

[millymoon]

Thanks Matt

Hi, Its the Ex here lol! We have checked for Vac from the red hose that runs from the OB valve to the wastegate actuator. That appears to be OK.... The rod on the wastegate actuator appears to pull down on wide open throttle albeit that it lifts slightly after a while - possible diaphragm problem or intake Vac equalising??
What we have found is that the motor does rev freely without the MAF sensor connected, although we are seeing black smoke from the exhaust??

Any ideas? :bang:

 

[matt8772]

sounds like the flow meter is gone and because its not been running right for a while its all coked up. had the same sort of thing on my brava 105jtd.

what i did was blanked off the egr valve with a bit of 1mm plate. then drove it around for a bit with the flow meter disconnected. a good hard thrashing sorted mine out, but beware if you havent had a cambelt done recently. if its still flat with the flow meter connected back up you might be looking at a flow meter.

 

[millymoon]

Thanks, do you mean the MAF sensor?? Hope that's not the case, this would mean the new one fitted is faulty....

The EGR was previously blanked off, but was removed and no change either way. Would this car run thru an MOT with an EGR & MAF disconnected?

 

[matt8772]

Thanks, do you mean the MAF sensor?? Hope that's not the case, this would mean the new one fitted is faulty....

The EGR was previously blanked off, but was removed and no change either way. Would this car run thru an MOT with an EGR & MAF disconnected?

yeah MAF stands for Mass Air Flow.

if the car runs ok with the new meter disconnected, but doesnt with it connected, id almost certainly say the new flow meter is faulty, but obviously i havent got the car in front of me so its dificult to diagnose something i havent had my hands on.

i would still blank off the egr valve though, especially on something of that age. more trouble than theyre worth and theyll affect your flow meter readings.

again difficult to say mot wise, you cant fail it for them being disconnected, but depending how much smoke its emitting depends on if it passes.

i really would block off that egr valve again, disconnect the flow meter and see what it drives like. if youve got an mot soon try chucking a fuel cleaner through it and a good, brisk road test and i reckon youll find the black smoke start to die off.

 

[millymoon]

Thanks so much for your help. I bought a cheap MAF sensor (I did tell the ex what MAF stood for - but me being a woman - he didn't listen lol!) so my mechanic tried an alternative MAF and the fault was still the same. Will def re:blank the EGR though. We've gone back to your original advice as we found that whilst revving the car to test the vacuum on the pipes, if the actuator rod on the wastegate was pushed manually the fault had gone, so either the actuator valve needs adjusting/replacing or there is a fault with the pipes. We located the very same fault on http://www.ilexa.co.uk/forum/index.php?topic=27813.0. I finally feel like I'm moving forward with this fault so really can't thank you enough. Hope your missus appreciates how much of a STAR you are!:worship: