Car wont rev???

R

rking

Senior Member
Joined
May 30, 2001
Here it is, the car wont rev. Starts right up, idles nicely for a 224/224 cam, but smells rich (may just be the cam or ???). This is on a fresh rebuild, new everything, and I mean everything!! Buildup is 75lb inj, MAF Trans + Gen 2, mod computer, Extender Extreme Chip, FP 45psi, blow through MAF, 3.5 MAF, FMIC, GTQ72, heated O2. I have already set the IAC and TPS. The car hasnt hit the streets yet, because of the problem.

Numbers at idle closed loop are:
IAC 23
TPS .46
cc are fluctuating nicely
BLM ~ 110
INT ~ 110
yes its rich, but will that cause it to not rev above 3000, with no engine load in park in the driveway?

However, car will not rev past about 3000rpm. And it smells rich.

I have set the Cam Sensor twice with a cam sensor tool.

You can hold the car at about 2800, via the scanmaster, try to give it a little more, falls on its face and will die if you dont feather it.

Coil is new, and I am pretty sure the Module is too. Ive checked the plug wires twice, but with this big of a cam its hard to hear if its missing and it does fire right up, so??

Any help or suggestions would be greatly appreciated!!!! I will post a video if I cant figure it out!! HELP!!! TIA
 
Are the valves being hung open by a valvetrain problem such as having too long of a pushrod? Maybe a MAFS problem?
 
Should the Vacuum gauge stay pretty constant @ idle? Could your grounds not be connected properly? Just a thought...
 
Im gonna ask a dumb question. Is your chip burned for the 75lb. injectors??
 
Bison: With the valve covers off, everything looks good. But looking at it is all I have done. The pushrods are stock length, so I wouldnt assume a problem there. As for a MAFS problem, if you mean Mass Air Flow Sensor, then it is brand new. I will take some AF readings tomorrow.

Cabech: Vacuum gauge stays right at 11 in Hg at idle, pretty decent for the cam. As for the grounds, I will recheck them, but I knew grounds on these things have always been a problem, so I double and triple checked them during the install.

86 TR: Yep

I just changed the plugs, the old ones had to be fouled, or close to it! They were sooty black and smelled of gas. I took the coil and module off of one of my other cars to try it out, I got the exact same problem, so it is definitely not that!! I once, a long time ago kind of had a similiar problem and it was the crank sensor. I checked the clearances and did a visual inspection of this crank sensor, and everything looks ok, but I am installing a new one tomorrow to rule it out. Any other suggestions!! Keep them coming, it really helps to hear everyones opinion!! TIA
 
another thought(guess) Does the TPS sweep steady from .46-wot? Maybe a flat spot? MAF sounds like its probable, could possibly be bad from the factory. Let us all know whats goin on!! I'm by no means an expert but learning myself(on these engines and modern GM cars!!) I thought that you want no more than like 7-8 Counts of IAC @ idle???
 
Thats a good guess. I will look at the TPS tomorrow. As for the MAF, its a new 3.5 LS1, I've never had a problem with these, but I will try to get some AF numbers tomorrow also and check it out. As for the IAC values. I always tune for 20 - 25 at idle. I have always been told thats a good place to start, so the IAC sensor has a good amount of adjustment that it can use up or down to smooth the idle...
 
rking said:
As for the IAC values. I always tune for 20 - 25 at idle. I have always been told thats a good place to start, so the IAC sensor has a good amount of adjustment that it can use up or down to smooth the idle...
Click to expand...

Ok, I must be thinkng of something else. Slap a TPS on & see whats up!!
 
Ok, did a little more checking.

TPS is good.

IC hoses are good, its a blow thru setup, so the only problems there would have to be within a foot of the TB.

Yesterday it would rev to around 3K cleanly. This morning it wouldnt rev past 2k. So its erratic :confused: ??

I do not have the valet or anti theft option.

I have a video of exactly how it sounds and what its doing that I will post as soon as it uploads.
 
All I have right now is the scanmaster and the gen 2, however, its running so bad there is no way that I would even consider driving it on the street for fear of washing out the rings or the bottom end. What kind of data would you be looking for from a car that wont rev past 2k while sitting in the driveway? I will see what numbers I can pull from it.
 
Data log would be good. Also, put a timing light on it and slowly rev it up and make sure nothing weird is happening there when it stumbles. Doesn't need to be a fancy delay light, you are looking for dropouts or big jumps when it is not supposed to. That will pretty much eliminate the crank and cam sensors and the coilpack/module. While idling are the coolant and mat sensors (and all the others too) reasonable?
 
Yeah, all the sensors are reading just as they should, nothing is really sticking out! MAT and coolant sensors are just fine.
 
ijames said:
Data log would be good. Also, put a timing light on it and slowly rev it up and make sure nothing weird is happening there when it stumbles. Doesn't need to be a fancy delay light, you are looking for dropouts or big jumps when it is not supposed to. That will pretty much eliminate the crank and cam sensors and the coilpack/module. While idling are the coolant and mat sensors (and all the others too) reasonable?
Click to expand...
The tach would be all over the place if it was a crank sensor issue or it would go to zero.
 
rking said:
The tach on the scanmaster should show the same problem.... Right??
Click to expand...

Tach on the scanmaster may not update fast enough. Make sure the balancer is tight and not moving in and out. Ive seen this before and it caused symptoms like you have but the tach would act up when it did.
 
I would do a factory reset on the Gen II, then run through your set up and configuration again. If the symptoms still persist, I would go for the connections.
You did solder everything? Thats #1 cause for problems.
 
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