Idle issues / MAF
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Joined: Sep 2007
Posts: 172
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From: Southampton, MA
Car: 89 Firebird Formula
Engine: 305 Vortec, Single-plane, 4 barrel
Transmission: T5, soon 700R4
Axle/Gears: 88 10 Bolt, Disc, Auburn, 3.23
Idle issues / MAF
Where to begin. 89 Formula, LB9 (305TPI).
I bought this car like a week ago, not maintained but in good shape. i tried some CRC MAF cleaner and I should never have. Car ran okay before but, misfired at and off idle a bit after. After probing the only wire that had over a volt on my MAF I got 0.59V at idle (around 1000).
Some BS article said the Bosch Hotwire should be like 2.5 and around 3.8 when you snap the throttle. Well, I got between 1.5-2.5 on the snap. So I figured I killed it. I got a new hotfilm MAF from Advance Auto and the car idles "great", almost no misses. but, very quickly after starting the engine, it drops to around 500RPMs and oscillates from 500-200 and often dies. I disconnected the battery hoping to do an idle relearn, but, I could not get the car to stay "lit". (Although, I am not farmiliar with this ECM/PROM; maybe there is no idle relearn. I only know the 730/V6 setup)
I guess it must be TPS/IAC or O2 related.(or ECM??) I am great with cars but, on systems like these, without a scanner it's hard to "guess" where to begin.
Technically the car idles better with the Bosch MAF that I thought was bad, it just misses.
I've got a '730, a MAP and a 730 harness (non-Fbody), but I don't think I have the patience right now to jump on the Speed Density bandwagon...
Sorry for the long post, I just need help. I'm trying to nurse this baby into shape, she has undercoat/no-rust, she needs to come back; and runs strong, just not currently.
Thanks,
Dave
P.S. I have also noticed much moisture in the exhaust,(since these issues) although it is only water.
I bought this car like a week ago, not maintained but in good shape. i tried some CRC MAF cleaner and I should never have. Car ran okay before but, misfired at and off idle a bit after. After probing the only wire that had over a volt on my MAF I got 0.59V at idle (around 1000).
Some BS article said the Bosch Hotwire should be like 2.5 and around 3.8 when you snap the throttle. Well, I got between 1.5-2.5 on the snap. So I figured I killed it. I got a new hotfilm MAF from Advance Auto and the car idles "great", almost no misses. but, very quickly after starting the engine, it drops to around 500RPMs and oscillates from 500-200 and often dies. I disconnected the battery hoping to do an idle relearn, but, I could not get the car to stay "lit". (Although, I am not farmiliar with this ECM/PROM; maybe there is no idle relearn. I only know the 730/V6 setup)
I guess it must be TPS/IAC or O2 related.(or ECM??) I am great with cars but, on systems like these, without a scanner it's hard to "guess" where to begin.
Technically the car idles better with the Bosch MAF that I thought was bad, it just misses.
I've got a '730, a MAP and a 730 harness (non-Fbody), but I don't think I have the patience right now to jump on the Speed Density bandwagon...
Sorry for the long post, I just need help. I'm trying to nurse this baby into shape, she has undercoat/no-rust, she needs to come back; and runs strong, just not currently.
Thanks,
Dave
P.S. I have also noticed much moisture in the exhaust,(since these issues) although it is only water.
Last edited by PV9685; Sep 18, 2007 at 11:02 PM. Reason: addition of data
Supreme Member
Joined: Aug 2004
Posts: 1,214
Likes: 3
From: Norwich, CT
Car: '89 Trans AM/'88 GTA
Engine: (2) Tuned Port L98's
Re: Idle issues / MAF
The only thing I can really suggest if you narrowed it down to a MAF problem is replacing it with a new Bosch unit, & nothing else.
I had bad idle problems.. basically rewired the electrical before I figured out the MAF sensors
I was putting in were out of calibration.
and yes, I know $300 bucks is alot to gamble with..
I had bad idle problems.. basically rewired the electrical before I figured out the MAF sensors
I was putting in were out of calibration.
and yes, I know $300 bucks is alot to gamble with..
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