I need help with my89
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Joined: Nov 2006
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From: warrenton mo
I need help with my89
hi everyone i have an 89 and I have just replaced the fuel pump and fuel filter IT HAS a great take off no misses {runs like it is supposed to but if you are into the throttle over have way and it shifts to second the moter drops out and doesnt want to run.
Under normal driving conditions as you drive and let it gain speed slowly it does alright in maintaining power.
I have racked my brain and have exausted all of my friends for the solution and cannot come up with one. Is there any one on here that can please help? Thanks
Under normal driving conditions as you drive and let it gain speed slowly it does alright in maintaining power.
I have racked my brain and have exausted all of my friends for the solution and cannot come up with one. Is there any one on here that can please help? Thanks
Le Mans Master
Joined: Oct 2003
Posts: 6,130
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From: seattle WA
First I'd check the fuel pressure at the schrader valve, then I'd ohm the TPS (throttle position sensor) should be around .54 volts closed throttle and steadly and smoothly increase as the throttle is opened to around 5 volts at wide open throttle. How about your cat..how old is it?
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Also, check your MAF. Mine would run great 90% of the time but if I really got into it it would start laying down. Turned out the MAF was bad and making it run super lean.
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From: Summerland B.C. Canada
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From: warrenton mo
thank you gentlemen
Wow I love this site! tHANK YOU TO ALL OF YOU FOR YOUR RESPONSE IT WILL DEFINITELY HELP ME TO GETTING MY BABY BACK UP TO THE WAY IT NEEDS TO RUN i APPRECIATE ALL OF YOUR SUGGESTIONS AND ADVISE
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From: warrenton mo
when I take off and romp on the accelerator it takes off like it should....when it shifts to second gear it acts like it is getting no fuel to the engine like its running out of gas!Once I shut the car off it is then back to normal and runs smooth again! As long as I dont step down over half way on the throttle it shifts and runs smooth but as soon as I floor it it spits and spudders until I turn it off and restart
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
For that I would attach a fuel pressure guage to the scharder valve and go for a drive. If the pressure drops when you experience the problem, suspect the new fuel pump.
It could also be a spark problem. How long since a tune up?
Disconnect the MAF and go for a drive...any difference?
It could also be a spark problem. How long since a tune up?
Disconnect the MAF and go for a drive...any difference?
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Thread Starter
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From: warrenton mo
well I had tuned it up last fall right before i parked it for the winter I did a presure test on my old fuel pump and replaced it and my new one is reading the 44-58 psi at key and drops 4 psi while running so i know i am alright there! I had disconnected my maf sencor and it is acting the same so right now i am back to being bewildered I supposed i will have to look into my cat being clogged next
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
The fuel pressure numbers that you posted seem a it high for a 89 too me. Is that with the stock FPR?
To check a clogged cat you can use a back pressure gauge at the O2 bung/boss, check for the cat glowing at night, or use a rubber hammer and tap on the cat and listen for rattling.
What did you replace when you did the tune up? coil, cap, rotor, plugs, wires???
To check a clogged cat you can use a back pressure gauge at the O2 bung/boss, check for the cat glowing at night, or use a rubber hammer and tap on the cat and listen for rattling.
What did you replace when you did the tune up? coil, cap, rotor, plugs, wires???
Melting Slicks
Joined: Apr 2002
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From: St. Charles, MO Route 66 Corvette Club
BE8UP: We have something in common as we both have a 89 Vette. A couple of questions for you:
1. Did you check for any stored codes in the ECM?
2. Have put any injector cleaner into the gas tank?
3. If you let the car start cold and then warm up while idling, what does the engine do as it goes into closed loop operation....... other that drop down in RPM? Any rough idle or misses noted?
4. Has the car been recently serviced or repaired by you or another person?
Some response to these two questions, please?
1. Did you check for any stored codes in the ECM?
2. Have put any injector cleaner into the gas tank?
3. If you let the car start cold and then warm up while idling, what does the engine do as it goes into closed loop operation....... other that drop down in RPM? Any rough idle or misses noted?
4. Has the car been recently serviced or repaired by you or another person?
Some response to these two questions, please?
Safety Car
Joined: Dec 2004
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From: Poop land
99% of these weird hiccup problems on 86-89 TPIs are caused by a faulty connection to the MAF or a faulty MAF itself. I'd troubleshoot from there.
And if your fuel pressure is dropping to 4 psi, that should also tell you something.
And if your fuel pressure is dropping to 4 psi, that should also tell you something.
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From: warrenton mo
Hi everyone
All of you gentlemen are awesome! {This is why we are CORVETTE owners}
I will try to repost all of your questions and give some sort of answer
1st I have not thrown any codes so there shouldnt be anything to check in the ecm
I have recently changed the fuel pump as my old one was only putting out 30 psi and then dropped to 22 while running
As far as my tune up it was your standard wire set from napa for the J code lt1 engine plugs and roter and cap
fuel filter and air filter has been changed other than that just fluid changes!
When I start it up it idles at 10 at first then drops to 7 rpm when i put it in gear it idles steadily at 6 and never jumps or drops
It runs smooth and extemely strong until i romp down on it like I previously described
I am planning on taking it down to have it put on a scanner to find out and replace any and all issues going on with it
I will post the outcome for all of you gentlemen if your curious
I do thank all of you for your infinite wisdom and ALL Together passion for the artwork we all know and love called corvette.
All of you gentlemen are awesome! {This is why we are CORVETTE owners}
I will try to repost all of your questions and give some sort of answer
1st I have not thrown any codes so there shouldnt be anything to check in the ecm
I have recently changed the fuel pump as my old one was only putting out 30 psi and then dropped to 22 while running
As far as my tune up it was your standard wire set from napa for the J code lt1 engine plugs and roter and cap
fuel filter and air filter has been changed other than that just fluid changes!
When I start it up it idles at 10 at first then drops to 7 rpm when i put it in gear it idles steadily at 6 and never jumps or drops
It runs smooth and extemely strong until i romp down on it like I previously described
I am planning on taking it down to have it put on a scanner to find out and replace any and all issues going on with it
I will post the outcome for all of you gentlemen if your curious
I do thank all of you for your infinite wisdom and ALL Together passion for the artwork we all know and love called corvette.
Safety Car
Joined: Dec 2004
Posts: 4,088
Likes: 0
From: Poop land
So are you saying that you 89 still has the same symtoms when you are trying to go full throttle? What is part/mid throttle feel like? Heavy throttle?
Sounds like your MAF sensor is freaking out. The sensor itself and/or the connection to the sensor is probably going bad. Disconnect the MAF sensor and gun it. Tell us if you are still having that weird problem. Also check to see if you have any vacuum leaks on those plethora of vacuum lines on the driver's side of the engine bay. Take it from my experience, vacuum leaks combined with a faulty MAF will make you feel like your car is unreliable.
Sounds like your MAF sensor is freaking out. The sensor itself and/or the connection to the sensor is probably going bad. Disconnect the MAF sensor and gun it. Tell us if you are still having that weird problem. Also check to see if you have any vacuum leaks on those plethora of vacuum lines on the driver's side of the engine bay. Take it from my experience, vacuum leaks combined with a faulty MAF will make you feel like your car is unreliable.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
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From: St. Charles, MO Route 66 Corvette Club
Be8up: Where are you going to take the car for a scan in the Warrenton, MO area? Just curious. I have a TurboLink scan tool that I use on my 89 and I live in St. Charles, MO.