i've been having this issue ever since I got this new motor in my 93(its hot cammed). If I shut the motor off and start it back up again after a few minutes, IE getting gas, then it will just SURGE so hard it throws you forward and back in the seat badly when I start to drive away. It usually takes a few minutes to stop doing that under light throttle and load. if I get the motor up in the rpms (above 2300) it won't do it. Is this a result of engine tuning? I had the computer tuned but had a major problem at idle (and still do) the computer would think that the right bank was going dead rich and it would lean it out so badly that it would run REALLY REALLY rough at low rpm. If we manually corrected the fuel trims every few seconds it would idle fine. I have changed O2 sensors and put 24lb ford motorsport injectors in AFTER the computer tune and it got a LOT better but its doing it to the point that its EXTREMELY aggrivating. Whats going on? ANY help or ideas would be GREATLY appreciated!! Thanks in advance!!! ALSO, the hotter the motor is, the worse it gets! The motor runs and drives great when its cold.


P.S. If I am missing any needed info just ask. Thanks again

 

Can you do some data logging? Just an Idea try disconnecting your MAF and running in speed density and see what happens.

 

hehehe its a '93 its already speed density Is there any other way I can record data?

 

Is it running rich?
My surge was a bad MAP sensor, $25

 

About the only way I would be able to tell if it was running rich or not is pull a plug I think, and we all know what that is like. The wierd thing is that it only surges/cuts out is at light throttle/clutch. At idle it just runs REALLY rough and shakes the car. On the laptop while the car was running we could see the computer pulling as much fuel out of the right bank as it possibly could.. While the left bank was running fine. We had leaned it out a ton, but it still did it. We did not lean it out any more because we were afraid of it hurting it. It seemed to really start after the guy who did my motor changed the fuel lines and put a clogged return line on. I have sinced checked fuel pressure while running and shut off, both were good. The vacuum line to the regulator was dry as a bone. I also changed the injectors after this problem as well. Could it have screwed anything else up? Thanks for the suggestions guys, I appreciate it! Was your map sensor doing the same thing?

 

anyone got any ideas?

 

Check the fuel pressure. As wierd as this sounds, my 94Z had the surge going on for almost 2 years before I figured out it was my fuel pump causing it. Once I changed the pump, it drove better than it ever had. It never completely failed on me, but it was obviously not up to it's full potential.

 

I checked the pressure and its within factor spec 40ish, BUT when the fuel line was clogged the pump was making a LOUD groaning sound... COuld it be that the pressure is fine when I am sitting still but when the car is all warmed up and I start it and go that the pump isn't keeping up?

 

???