Fuel sytem questions.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 855
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Fuel sytem questions.
If any of you have been following my fuel pump problems then you know whats going on, but here is my question: What could cause my injectors not to pulse properly? I replaced the fuel pump, strainer, filter, and ECM. My car still runs lean and injectors will only pulse to about 4.0 ms before car feels like its running out of gas. The max pulse at WOT was only 7.4 ms. I even recorded a few 0.0 ms pulse. That is telling me the injectors are not opening fully or at all. Could a bad FPR cause this? TIA.
Melting Slicks
Joined: Apr 2001
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From: Ca.
Re: Fuel sytem questions. (Rick86)
So, were you able to check the fuel press? If its ok then....the 0.0 ms pulse width-was that on decel? If so thats norm, however if it was with your foot in it -not norm! The ecm has "drivers" for the injectors, but if you've replaced that, onto the next. The injector on is a ground on controlled by the ecm. Check if you have a bad connection somewhere in the ground on wire or also check the other + volt. wires to the injectors for con't voltage. Oh yea, elec. can be fun. :cry
Burning Brakes
Joined: Feb 2000
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From: SF Bay area, CA USA
Re: Fuel sytem questions. (Rick86)
I read your last post and you said you tested the TPS and it was o.k. Did you watch the voltage as you open the throttle? It should rise steadily from around .52 volts to over 4.5 volts at wide open. Open the throttle slowly and watch the meter for any dead spots.
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Re: Fuel sytem questions. (AquaMetallic94LT1)
Aqua,
This is also what I was thinking. We really need to know the MAF readings. The injecctor pulse width you get from the scanner is not necessarily what the injectors are doing, but rather what the ECM is commanding.
Here is a graph of what the TPS, MAF, and Injector PW is doing during a run on my '86 convertible.
Good luck.
[Modified by Ray Quayle, 7:17 AM 9/5/2001]
This is also what I was thinking. We really need to know the MAF readings. The injecctor pulse width you get from the scanner is not necessarily what the injectors are doing, but rather what the ECM is commanding.
Here is a graph of what the TPS, MAF, and Injector PW is doing during a run on my '86 convertible.
Good luck.
[Modified by Ray Quayle, 7:17 AM 9/5/2001]
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 855
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Re: Fuel sytem questions. (AquaMetallic94LT1)
I wonder if your MAF is bad. Its possible that its giving false readings confusing the ECM.
I still haven't bought a fuel pressure gauge, I went looking for one, but I didn't like the gauges. The fuel hose didn't look long enough to tape to the windshield, and the increments went in 10 lb increments with only 4 tick marks in between. I want a better quality gauge with at least 1 lb increments. I'm holding out for a digital FP gauge to mount in gauge pod. Thanks for the help
