car won't idle, stock boost gauge acting funny...

[riddlejason]

Hi guys, my 91 GVR4 had been running poor for the past few days and until yesterday I can't even get it started, it cost me a fortune to tow it today. The stock boost gauge is showing boost while it's in light throttle. Even at idle, I gotta keep my foot on the peddle in order to barely keep it idling. Again, the stock boost gauge was showing boost at idle. I cracked open the repair manual and checked the MAF connector and the harness with my trusty multimeter and they are fine. I also replaced with another MAF from a known good source and didn't solve the problem. I understand the stock boost gauge is driven by the ECU which receives signal from the MAF. Logically I will try another ECU, but before I throw in more $$, I want to hear from you guys' opinion. thx

 

[GSTwithPSI]

I would start by checking the mechanical timing. Turn the motor over until the until rank reads TDC and make sure your cams are lined up (marks even straight across and dowels at 12 o'clock).

Do you have any means of data logging? It would really make it easy on you if you had a logger or something, so you could see what your ECU is seeing.

 

[prove_it]

Check your ecu for a bad board. There is a sticky regarding checking your ecu caps or your car will explode. Read through that.

 

[bradrs]

Have you checked for boost leaks?

 

[riddlejason]

Thx for the help guys. The mechanical timing should be fine. It was running fine before until this happened. I don't have a data logger, wish I do though. It has to do with fuel, the engine is being flooded. I hate to think that the TPS has gone bad since it's the backup of the MAF.

 

[riddlejason]

Not yet, I will check that today as well as the ECU. Will keep u all posted. Thx again

 

[riddlejason]

checked all the plumping today, they are all good. Took the ECU out and opened it up, the capacitors still appear to be dry, no trace of leaky caps. Any idea will a 1990 GVR4 ECU run in a 1991 model? many thanks

 

[tektic]

no. wiring is different

 

[riddlejason]

problem solved. Got a faulty fuel quantity gauge. many thanks for the help guys.