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Poor running car.

gvr4ever

Well-known member
Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
I've had this problem for awhile now and I can't solve it. Runs like junk cold. Rich, hesitating, rough, etc.

Car has good compression (rebuilt head) cleaned and matched injectors and a injector noid light had confirmed the injectors are getting power. Car has tested another CAS, coil pack. Power is getting to the spark plugs and it has brand new plugs. No error codes, no boost leaks. Vacuum looks good on the boost gauge. Base timing and fuel pressure has been checked over and over again.

Any ideals?

Could a MAF fail without a CEL? Whatever the issue, it seems to be a fuel air ratio problem.
 

92_talon_awd

Well-known member
Joined
Feb 11, 2014
Messages
456
Location
Knoxville, TN
How are your temp readings (ECU, not gauge)? I had a coolant temp sensor go bad on my 1g, never set off a CEL but the car thought it was unbelievably cold, like arctic winter cold. Tried to richen it up like crazy.
 
Last edited:

gvr4ever

Well-known member
Joined
Aug 6, 2002
Messages
6,190
Location
central Indiana
I'll have to fire up the logger and check that out. I hope its that simple.
 

92_talon_awd

Well-known member
Joined
Feb 11, 2014
Messages
456
Location
Knoxville, TN
When that was happening with my car, my new plugs would be crazy black within a few minutes. It was a pain in the butt to even get started and when it did start it ran very rough. I had just done a head gasket so it took a minute to figure out what was going on. /ubbthreads/images/graemlins/banghead.gif When I checked the voltage from the sensor and matched it up to what temp it corresponded to, it was something like -50 degrees.
 
Last edited:

prove_it

Well-known member
Joined
Jul 3, 2008
Messages
4,201
Location
Sioux Falls, SD
One thing to note is that the CEL diag is a really basic system. It really only looks for opens and shorts. It has no logic and doesn't think about the readings. So to answer your question about a failed MAF with no code, yes it can happen. Any OB1 system is pretty limited in its ability to detect issues. That's why a datalogger is really your best friend.
 
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