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Long Start No Acceleration


Gsmith400

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I need some help my 94 ls 400 out of no where developed a problem all the time it take about 10 seconds of cranking for it to start then if i bearly give it gas it will accelerate but if i drive it normaly past 2000 rpms it will bog and not let anytihing happen i changed both coils wires plugs fuel pump ecu efi relay fuel pressure dampener i dont know what the deal is also when its running its smooth as can be but there is a constant check engine light on and it will not let me check it any help would be great

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I need some help my 94 ls 400 out of no where developed a problem all the time it take about 10 seconds of cranking for it to start then if i bearly give it gas it will accelerate but if i drive it normaly past 2000 rpms it will bog and not let anytihing happen i changed both coils wires plugs fuel pump ecu efi relay fuel pressure dampener i dont know what the deal is also when its running its smooth as can be but there is a constant check engine light on and it will not let me check it any help would be great

Sure does sound like a fuel starvation issue but you should try to retrieve codes before you go any further with the parts changing. Did you try retrieving the code(s) using this procedure? -> http://www.lexls.com/tutorials/intro/codereading.html

Right off hand, it sounds like a plugged fuel filter and also maybe a leaky injector. But try the codes first and let us know what you find.

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Tried to pull codes the light just stays on no flashing i work at autozone so i just bought a fuel filter also i replaced all orings on injectors and bench tested them and there working peoplery would fuel starvation cause a constant code?

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Tried to pull codes the light just stays on no flashing i work at autozone so i just bought a fuel filter also i replaced all orings on injectors and bench tested them and there working peoplery would fuel starvation cause a constant code?

With the advent of full adoption of OBDII jumpering the 2 pins in the OBDII connector does not "flash" the CEL to determine the fault, you need a reader for that. At least that seems to be the way in both my '95 LS and '01 RX. Jumpering will still "flash" the non-EPA mandated emissions functions, ABS, VSC, etc.

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i changed both coils wires plugs fuel pump ecu efi relay fuel pressure dampener

Are you saying you've changed both coils, 8 plug wires (I assume the coil wire as well, making ten wires), 8 spark plugs, 1 fuel pump, 1 fuel filter, 1 engine ecu (really you swapped in the ECU???), efi (fuel pump?) relay, and fuel pressure regulator/dampener? That is a lot of changes. 33 separate components..

First off I'd stop swapping parts. In addition to being expensive you're just adding more variables into the diagnosis.

I would put everything back that is easy to do related to the fuel pump. That is the old relay, the old dampener and I'd put the old coils back in too. If you did swap the ECU that needs to go back to the old one too. I would double and triple check the ignition wiring and orientation of caps on the distributors. Download a wiring diagram and check it back to the factory diagram and not your recollection. Get it so it at least is running, maybe not well but running. Then you can pinpoint testing at root cause.

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Its an obd 1 connector pre obd2 i know no other way to check them other than a jumper wire also i did not replace the ecu in the trunk above the passanger side wheel hump there is a fuel pump control or fuel pump ecu at first i thought it was an ignition problem from some other post on this site when i baught the car it had a miss that is when i replaced plugs and wires when this new issue started i read some posts saying it was coils not supplying enough volts under a load and there was no change then i noticed a clicking on the driverside fuel rail from the fuel dampener the reg is on the passanger side then someone thought it could be the fuel filter. Changed it and now it wont start just cranks but the ls400s ECU is still the same all i did was change the parts thay other people were having the same issues i just need some other thought so i can get this thing running

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Best run-on sentence I have seen in quite a while. So you suspect no fuel at the injector rails, correct? You could try hooking up a fuel pressure gauge to see if you have proper pressurization. You could also press the valve on the rail to see if any fuel squirts out. And a simple test would be to spray some starter fluid into the throttle body and see if you could get the engine to run momentarily. That does not solve the problem but does isolate your issue to the fuel side.

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Sorry about the senyence im on my phone. Well i chevked fuel and every thing is good there. Also starter fluid does nothing.

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On a phone? Ok, that explains it. Well, if the starter fluid does not get a 'rise' out of the old gal, you can check for spark. Pull each main distributor wire, hold close to the block while cranking (I use a screwdriver with substantial plastic insulation so as not to frizz my hair) and see if there is a light show.

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i just need some other (Parts?) thought so i can get this thing running

Wrong, you need fewer parts. Start putting back the old parts and retrace your steps. Throwing parts at a car is not going to solve it if you don't understand the root cause problem.

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Ok there is no spark and timing checks out

.

Now you start tracing back to coils, ignitor, fuses, connectors, sensors, ecu. If you replaced the ECU and have the original, I would put it back in place first.

What timing checks out?

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Ok i got it started. But same problem it takes 4 to 5pull sec to start. When i slighlty press the gas it will drive. But when i half throtle or floor it it just bogs down. Now i do have the common egr pipe leak and there is a weird ticking coming from the drivers side fuel rail. The ticking increases with rpm. Also i dont know if this matteres but my tranmission has not had reverse since i got the car.

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Coils are a common problem on this car. With engine running pull the coil wire off one bank to the distributor. See if the car stalls out. Then reconnect wire, restart car and try the same thing on the other coil.

If one coil is bad then unplugging it should make no difference. The car will continue to run but run poorly. If you disconnect the good coil then the car will stall because it won't have any spark left.

If these tests don't make any difference then I'd dig into that ticking noise. Maybe you have a faulty injector (but its hard to see how one injector would cause such a dramatic performance hit).

Why are you putting time and money into a car that has no reverse? Isn't that kind of important?

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Ok i got it started. But same problem it takes 4 to 5pull sec to start. When i slighlty press the gas it will drive. But when i half throtle or floor it it just bogs down. Now i do have the common egr pipe leak and there is a weird ticking coming from the drivers side fuel rail. The ticking increases with rpm. Also i dont know if this matteres but my tranmission has not had reverse since i got the car.

Well, I would kind of like to know what you did to get it started. Might help in the diagnosis. No reverse, huh? Have you ever investigated the trunk wiring that is notorious on this vintage? I do not know if it would affect the operation of the transmission but its worth having a look.

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Well i baught tje car cheap and a tranny for it is 450 so just waiting for tax time. But what i did to get the car started was let the battery charge for 30it min . Then i just let it crank and about 15 sec of cranking she started

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Well i baught tje car cheap and a tranny for it is 450 so just waiting for tax time. But what i did to get the car started was let the battery charge for 30it min . Then i just let it crank and about 15 sec of cranking she started

Well I guess not having reverse is better than only steers to the right.... :chairshot:

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  • 2 weeks later...

Gsmith400,

No reverse is probably due to seals being shot in the tranny. My '92 had over time begun to lose reverse - it would take more and more time before it would go into reverse, but it would do so eventually. finally, when it began to lose front gears, I had the tranny rebuilt, and no more problems. The shop owner (very reputable) told me the seals were hardened and needed to be replaced. If you do have the tranny redone (most likely any replacement - read that used will also have the seals losing their flexibilty due the environment or abuse!), make sure to have the shifter solenoids changed as well, or you will have shifting problems - the A341E is apparently notorious for having these solenoids getting clogged up over time.

By the way is your starting problem resolved? From what you have described, you may simply have a low battery problem. These cars have a heavy load requirement, in my opinion. Try borrowing a new battery and see whether your problem resolves, and let us know.

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