88 starts then dies after 3 seconds
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88 starts then dies after 3 seconds
I have a 88 firebird TA 5.0 F that I have owned since 1990, it has 260,000 miles with everything original. The fuel pump was replaced about 10 years ago and the MAF replaced 6 years ago.
A couple of weeks ago, it failed to start in a parking lot in town, it had no fire after testing a spark plug wire, I replaced the ignition module in the store parking lot, but no luck. Had it towed home.
Started testing ignition parts, coil failed voltmeter test, and wires from the pickup coil in distributer had rotten insulation that was cracked in multiple places. I paid a mechanic friend replace distributor, coil, cap, rotor with rebuilt one from O'Rieleys. Car would start, but wouldn't run, sometimes idle rough for 10 seconds, if the gas was touched, it fails immediately.
I borrowed a fuel pressure tester, and found 45 pounds after key switched, and running in "limp mode with MAF unplugged"
Checked codes - 2 stored 33 & 34 related to MAF, but reportedly may be caused by rough idle
This weekend mechanic friend loaned me his MATCO computer that I connected via the under dash port, I noticed that the values for the CTS were shifting wildly between 30 & 160 almost too fast to notice, MAF, IAC (value high), TPS appear in acceptable range at idle. I replaced the CTS and checked the IAC (IAC replaced 6 years ago). Car started and ran fine multiple times, with good idle after warming up, MATCO observed both open and closed loop conditions, everything appeared normal.
Today back to start OK, rough idle 3 seconds, then dies, if the gas pedal is touched it dies immediately. Sometimes it runs longer but the idle is seeking, i.e. running extremely low (almost sounds like a hotrod with a big cam), then recovering, then dies. Codes 33 & 36 now (codes cleared yesterday when running fine) MAF and MAF burnoff.
According to the MATCO the IAC value of 145 is too high, but I have read that the computer shows where it should be not where it is? Should the values for the TPS change as the throttle is changed? It stays at 54 no matter where the throttle position is.
It runs fine in "limp mode", but gas mileage will be terrible, seems the more I understand about this, the less sense it makes............
Any ideas?
A couple of weeks ago, it failed to start in a parking lot in town, it had no fire after testing a spark plug wire, I replaced the ignition module in the store parking lot, but no luck. Had it towed home.
Started testing ignition parts, coil failed voltmeter test, and wires from the pickup coil in distributer had rotten insulation that was cracked in multiple places. I paid a mechanic friend replace distributor, coil, cap, rotor with rebuilt one from O'Rieleys. Car would start, but wouldn't run, sometimes idle rough for 10 seconds, if the gas was touched, it fails immediately.
I borrowed a fuel pressure tester, and found 45 pounds after key switched, and running in "limp mode with MAF unplugged"
Checked codes - 2 stored 33 & 34 related to MAF, but reportedly may be caused by rough idle
This weekend mechanic friend loaned me his MATCO computer that I connected via the under dash port, I noticed that the values for the CTS were shifting wildly between 30 & 160 almost too fast to notice, MAF, IAC (value high), TPS appear in acceptable range at idle. I replaced the CTS and checked the IAC (IAC replaced 6 years ago). Car started and ran fine multiple times, with good idle after warming up, MATCO observed both open and closed loop conditions, everything appeared normal.
Today back to start OK, rough idle 3 seconds, then dies, if the gas pedal is touched it dies immediately. Sometimes it runs longer but the idle is seeking, i.e. running extremely low (almost sounds like a hotrod with a big cam), then recovering, then dies. Codes 33 & 36 now (codes cleared yesterday when running fine) MAF and MAF burnoff.
According to the MATCO the IAC value of 145 is too high, but I have read that the computer shows where it should be not where it is? Should the values for the TPS change as the throttle is changed? It stays at 54 no matter where the throttle position is.
It runs fine in "limp mode", but gas mileage will be terrible, seems the more I understand about this, the less sense it makes............
Any ideas?
Last edited by clemsfl; Mar 28, 2010 at 02:01 PM. Reason: TPS value was backwards
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