98 GX Won't Start

[Jay98]

I just bought a 98 GX which was not running. The previous owner said that the fuel pressure regulator had a ripped diaphragm, which I verified. I replaced the FPR with a new one from Honda ($1500), but it still won't start. It sounds like it tries to start, but never quite does.

I filled the fuel tank so that is not the problem.

I checked for error codes from the PCM, but there are none (although the computer may have been reset when I disconnected the battery). Still, I checked them again after many attempts to start it, and there are no codes.

I can hear the solenoid valve shuttle in the tank when I turn the ignition on, and some clicks from under the hood. However, the solenoid valve must shut off while I'm trying to start it, because it doesn't make any noise when I turn the key off. What I mean is that I turn the key on and it clicks. I try to crank it and then release the key back to the run position. Then I turn the key off and there is no click. Then I turn the key back to run and it clicks again. Is this normal?

I disconnected the outlet fitting from the FPR, and verified that there is fuel pressure at that point after cranking. The car sat for a couple of years, but I can't believe that all four injectors could have gone bad.

I haven't checked yet for spark at the plugs, but since it tries to start, it seems like it must be getting a spark.

It seems to me like the PCM gets unhappy while the car is trying to start and closes a valve or disables the injectors to prevent it from starting. But, you would think that this would result in an error code.

Does anyone have some suggestions about how to further troubleshoot this with a scan tool and ordinary mechanics tools? I want to do everything I can before I take it to a Honda dealer.

Thank you,
Jay

[Jay98]

Re: 98 GX Won't Start

I spent the weekend troubleshooting and eliminating possible problems. It is definitely a fuel problem, since I can get it to start and run for a few seconds on starter fluid.

I also got it to start once on CNG with the throttle at WOT. It ran very rough and very slow for a few seconds and then died.

I also changed the high pressure fuel filter. The old one had split down the side. Some filter material came out when I drained the filter housing. I'm wondering if perhaps this led to the failure of the fuel pressure regulator.

Perhaps the injectors were fouled as well. Can anyone suggest how to flush the injectors?

Jay

[Curtis]

Re: 98 GX Won't Start

Jay, there are companies listed that can rebuild the injectors for about $50 each. A search for rebuilt injector should turn them up. I think their in the parts exchange thread. You may also be able to locate someone in your area that can flow test them to determine their condition.

[Jay98]

Re: 98 GX Won't Start

More troubleshooting results:

1. Injector "Noid" light test: I crank the engine and the Noid light flashes a couple of times while the engine tries to start, but then stops flashing for a few seconds while engine cranks. If I continue cranking, it just continues to cycle through this pattern, trying to start every few seconds.

2. I downloaded the troubleshooting procedures from Helm (chapter 11). This led to replacement of the injector control module ($240), but the problem persists.

3. I checked the resistance of the three sensors in the distributor and they all checked OK. On a whim, I replaced the distributor with one from a junk yard ($120). The resistance of its three sensors also check out. Still doesn't start.

4. I checked the ECU relay, the injector relay, all of the fuses, and all of the wiring between the distributor, ECU, injector control module, and injectors. They all check out good according to the Honda troubleshooting procedures.

5. The Honda troubleshooting procedures are now telling me to replace the ECU with a "known good unit." I really hate to shell out another $600 at this point for an experiment. The MIL is not lit, and I still don't get any codes, so I am having a hard time believing that the ECU is at fault.

Does anyone have a spare ECU I can use to test?

Does anyone have any other suggestions?

Thanks,
Jay

[Curtis]

Re: 98 GX Won't Start

Have you determined the condition of the pressure regulator/s?

[Jay98]

Re: 98 GX Won't Start

That was the first thing I replaced. It is brand new.

[karlhafen]

Re: 98 GX Won't Start

Just two thoughts. A couple things things I have seen on various gasoline cars. (ymmv on a GX)

If one of your injectors is shorted it might be pulling down the voltage. Try unplugging all the injectors and trying your noid light again.

I do not know if a GX has clear flood mode (cutting fuel if the throttle is wide open while cranking). Read your tps voltage on the scanner. Most cars are about .5v closed and 4.5v at wot. A shorted tps will usually read 5v. and cause the injectors to be shut off until the rpm is high enough. If your tps appears to be wrong unplug it and see if the car starts.

[Jay98]

Re: 98 GX Won't Start

Thanks for the tip! It turned out to be a broken TPS ground wire (yellow/red). I actually found it before I saw your post, but you were probably correct about the clear flood mode. It also explains why I was able to get it to start (barely) with the pedal at WOT. The car runs great now.