Despite my efforts this week we have yet again reached a dead end. Any ideas?

 

I have recently changed engine of my z but when it deccelerates it stalls or it revs at idle from 200 rpm to 2000 rpm. My mechanic has found that there is no signal going from the ecu to the fuel pressure regulator. When the fuel pressure regulator is given power indepentenlty then the problems seems to stop. (power to it is given straight from the battery randomly). Any ideas why the ecu is not giving power to the fuel pressure regulator? the ecu was fine before engine change. help!!!

olympiacos,

 

Lets assume all the vacuum pipes and connections are correct I think you may be chasing the problem from the wrong direction.

 

The ecu may well seem to not be outputing a signal to the fuel pressure solenoid but it may be doing this because other errors are present and is compensating for them.

 

Check both butterfly stop postions are correct ie ( synchronised )

Check throttle bodies are clean

Check throttle postion switch

 

Then it is vital to get the base idle setting correct.

 

This is best achieved with the engine warmed up and with the auxilary air valve disconnected, the engine revs will most likely drop lower, then adjust the by pass screw in the side of the aux air valve to stabilise the tickover to arounf 850rpm, switch off the engine and re-check, if ok reconnect air valve and revs will rise and then fall slightly to a slightly high tickover around 950 rpm.

 

Switch off the engine and wait 10 seconds or so and start up the engine again the engine should now idle correctly.

 

With now correct connections, piping,tps, clean throttle bodies and synchronised throttles the base tickover will be the last thing to check.

 

What you have done by this stage is elliminate problem area`s which could give an unstable or incorrect signal at the ecu which in turn could be trying to compensate for.

 

From the information you mention then hopefully that should solve the problem.

 

If you have access to a ConZult it is soooooo much easier to do this!!

 

Jeff @ Zedworld

Thanks Jeff,

 

i will pass the info to my mechanic. What is a ConZult by the way?

If it is a Z specialist unfortunately there is no one in Cyprus. Z's are very rare.

H iOlympiacos

 

conzult is a diagnostic program which runs from a laptop. If you have access to a laptop you can buy the software fro Danny at DTA via the traders section on this forum.

 

Cheers

 

Robin