97 D1 won’t accelerate

boxster

Well-known member
Jun 1, 2009
182
13
Fallbrook Ca.
D1 starts but won’t gain speed, had this happen 4 years ago was failed fuel pump. Recently replaced fuel filter and fuel pump, changed spark plugs, replaced damaged CKPS connector all with no resolve and no CEL. MAF sensor replaced 4 years ago so next I replaced MAF with known working MAF no change. Cleaned MAF and TB and IAC Valve no change. Test drove and ran erratic but no stall out and no CEL. I’m ruling out fuel pump and MAF. However I’m thinking that the IAC could be failing it original unit because of the erratic idle. Any ideas?
 

fishEH

Well-known member
Jan 26, 2009
6,905
179
Lake Villa, IL
Your description leaves something to be desired.
Does the engine rev but you don't accelerate?
Does it not rev at all?
Is it hiccuping or bogging down?
 

boxster

Well-known member
Jun 1, 2009
182
13
Fallbrook Ca.

boxster

Well-known member
Jun 1, 2009
182
13
Fallbrook Ca.
If you disconnect the MAF sensor the system knows its out of the circuit and meters fuel with all the other inputs it has available.
I runs great unplugged, I tried two different Mafs the one on it and another supposed good one neither work. Any ideas?🤷‍♂️
 

discostew

Well-known member
Sep 14, 2010
6,417
497
Northern Illinois
I like to tape my fuel pressure gauge to the windshield and see what it's doing under load. I know it's a new pump but maybe it can't make enough volume. Power ground whatever.
I only trust a MAF sensor if it's in a truck that's running good. That's why they call it a known good sensor.
 
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Trent and his Rover

Well-known member
Jun 25, 2006
124
1
D1 starts but won’t gain speed, had this happen 4 years ago was failed fuel pump. Recently replaced fuel filter and fuel pump, changed spark plugs, replaced damaged CKPS connector all with no resolve and no CEL. MAF sensor replaced 4 years ago so next I replaced MAF with known working MAF no change. Cleaned MAF and TB and IAC Valve no change. Test drove and ran erratic but no stall out and no CEL. I’m ruling out fuel pump and MAF. However I’m thinking that the IAC could be failing it original unit because of the erratic idle. Any ideas?

Compression?