make sure the wires to it are not melted and shorting out. 
check the temp sensor and connectns that goes to the puter.
Bad TPS? OR?
Thread Starter
Drifting
Joined: Mar 2008
Posts: 1,809
Likes: 441
From: Denver CO
Bad TPS? OR?
I've been chasing a gremlin in my 84 that pops lt ugly head after about 30 min of driving.Ive replaced every sensor/ ignition part/ CAT/ fuel pump / o2 sensor w/the exception of TPS /PU coil and ECM, As stated in other threads car runs great then fails on its face.To me seems to be heat related. NO CODES NO SEL. My question is if the TPS goes haywire could it tell the ECM that the throttle plates are closed when actually there not.Car will idle but runs like its super lean.No power. Plugs also reflect that.Pops out TB. OR could the timing be getting retarded somehow?Help!!
Last edited by gjohnson; Nov 13, 2015 at 12:46 PM.
Race Director
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Pro
Joined: Jan 2003
Posts: 706
Likes: 47
From: Denver Colorado
Do you have good fuel pressure? Should be about 13 PSI all the time. The Cross-Fires are real sensitive to fuel pressure and the 1984 fuel pumps are not real good at sustaining steady pressure. A fix if the pressure is low is to install a 1985 or later TPI fuel pump. I know you put in a new pump but, the 1984 ones have difficulty with maintaining pressure. If you do not know the TPS is good, the test procedure is in the Factory Service Manual, you need a Volt-Ohm Meter, and replacements are not too expensive. My bet is the fuel pump is marginal and fuel pressure drops below 13 PSI under load when it warms up.
Thread Starter
Drifting
Joined: Mar 2008
Posts: 1,809
Likes: 441
From: Denver CO
oops. replaced that too! I did pull the ecm today and its already been replaced w/a sticker that reads Delco Elec. factory authorized reman.module #01226026 so I'm hopin that takes that out of the equation Thanks for the replys everyone
Last edited by gjohnson; Nov 13, 2015 at 03:50 PM.
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Team Owner
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The aggravating part of the P/U coil is that it requires removal of the distributor from the car and a bench replacement of the part. Maybe why you've avoided it?
Thread Starter
Drifting
Joined: Mar 2008
Posts: 1,809
Likes: 441
From: Denver CO
Ive still got that to check in real time. I'm gonna tee the line and tape the gauge to the windshield and drive it untill it acts up. I have had a new fuel pump malfunction on my truck before.
Team Owner
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A later style GM HEI (NOT coil in cap) but same/similar symptoms. First thing we did was pull the cap and the connector pole piece/ PU coil to module was corroded so out with the distributor, replaced pole piece/PU coil and there was no further issues. Done. Best I recall mine would start when HOT but stumble, it's been many years ago, many years.
Didn't futz with anything else. First thing we went to after a "tap test" on the ECM.
Didn't futz with anything else. First thing we went to after a "tap test" on the ECM.
Last edited by WVZR-1; Nov 15, 2015 at 04:34 PM.
Thread Starter
Drifting
Joined: Mar 2008
Posts: 1,809
Likes: 441
From: Denver CO
A later style GM HEI (NOT coil in cap) but same/similar symptoms. First thing we did was pull the cap and the connector pole piece/ PU coil to module was corroded so out with the distributor, replaced pole piece/PU coil and there was no further issues. Done. Best I recall mine would start when HOT but stumble, it's been many years ago, many years.
Didn't futz with anything else. First thing we went to after a "tap test" on the ECM.
Didn't futz with anything else. First thing we went to after a "tap test" on the ECM.
Last edited by gjohnson; Nov 15, 2015 at 07:42 PM.
Melting Slicks
Joined: Jan 2001
Posts: 2,996
Likes: 304
From: MOORESVILLE NC
I've been chasing a gremlin in my 84 that pops lt ugly head after about 30 min of driving.Ive replaced every sensor/ ignition part/ CAT/ fuel pump / o2 sensor w/the exception of TPS /PU coil and ECM, As stated in other threads car runs great then fails on its face.To me seems to be heat related. NO CODES NO SEL. My question is if the TPS goes haywire could it tell the ECM that the throttle plates are closed when actually there not.Car will idle but runs like its super lean.No power. Plugs also reflect that.Pops out TB. OR could the timing be getting retarded somehow?Help!!