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engine start


LarryK 87

When i start the engine, it fires immediatly, BUT, the Idle is very high 1200 - 1400 rpm, Now this cannot be good for the engine( especially on startup), it then settles down to around 800- 900.
Idle will cycle between 800- 1000 after warm up.

Any Idea's? Anyone?

Some Things of note:
Missing Vacuum Tank ( line plugged off )
New Plugs,Cap, Rotor, Cables
Just Cleaned TB, and, has generated no error codes(yet) since i ran a can of SeaFoam cleaner through the injectors ( was generating code 44)

Fuel Pressure = 42.0 psi @ engine off/Ign on
= 36.0 psi @ Engine running.
MPG is baaaad, maybe 5 - 7 mpg ( mostly city driving)

Things i have not replaced, but need to:
O2 sensor
Fuel Filter
92k miles on engine.


Gone but not forgotten
Jan 30, 2001
Hermosa Beach, CA
1987 Z51 Silver Coupe
Just lookin' for posts with no replies...

Larry, I don't understand why there is no vacuum cannister? :confused

When you cleaned the throttle body, did you clean it "on the car" or on the bench? Was the IAC cleaned and adjustment checked? Was the TPS removed, and if so, was it re-calibrated when re-installed on the throttle body? Are all of the gaskets on the throttle body new or in good condition and sealed properly? Are all connections on the air inlet before and after the MAF sealed tightly?

The oxygen sensor would cause the engine to run rich if it was malfunctioning, but the idle wouldn't necessarily be any higher. It would cause you to get that kind of gas mileage that you describe though.

Your fuel pressure sounds ok, but it would never hurt to change the fuel filter. That's a lot of miles if it is the original filter. ;)

Good luck.

LarryK 87

as to the missing canister... dont know, was really more curious if it would bother anything if it was missing.

The TB was removed and cleaned on the bench, Yes the TPS was removed ( and readjusted to .54vdc ), IAC was replaced with a new one. All gaskets appear in good shape. No appearant sounds of a vacuum leak( that i have seen anyways).

O2 sensor is, well i will assume, original, and since i cleaned the injectors, have not gotten a lean condition code from the ECM. As a side note then guy at the shop said there should be 2 of them(O2's) one on each side, his reasoning is being TPI and Odd/Even injectors and fuses would mean L & R O2 sensors, Have not spotted the one on the right side if it is there, but maybe just did not look carefully enough ( Left side is obvious )

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