Guest rustfarmer Posted February 15, 2011 Share Posted February 15, 2011 Freshly built 6 ran fine then within 1000 miles and all new sensors, became hard to start progressively worse, checked ECT sensor and resistance was 16K at 60 degrees F which my (crappy) Chilton book shows a chart which indicates 16K as below 20 degrees. So, I go to my parts store and check a new BWD part and it reads 10K at 60 degrees, better but still way off by the chart. Test another different brand (master pro) and get same reading, so I install the BWD aprt and my problem seems fixed. WTF? Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted February 15, 2011 Share Posted February 15, 2011 I am replying to myself. Found that I was using the wrong spec's and in fact resistance for this part should be near 10K at 65 degrees, so, sorry 'bout that. I withdraw my question, and hope I did not waste too much of anyone's time. Link to comment Share on other sites More sharing options...
Guest My TC Toy Posted February 16, 2011 Share Posted February 16, 2011 Glad we could be of help. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted February 22, 2011 Share Posted February 22, 2011 Spoke too soon, car has failed again exactly the same. To start must pump the gas pedal like mad, but once started runs normally until shut off. It is my understanding that while starting, the ECU is only looking at inputs from the IAC,coolant sensor, and MAP sensor. As I have said, all sensors, ERG, plugs, wires, cap and rotor are new, except I believe the MAP sensor may be the only old part. I will test it this week and possibly replace it as a test since it is cheap. Any other ideas most welcome. Link to comment Share on other sites More sharing options...
TwinCamFan Posted February 22, 2011 Share Posted February 22, 2011 So the car runs normally once started, no codes, no stalling until you shut it off? Just trying to get a clearer picture of whats going on. I've checked the Coolant temp sensors and found them out of spec and replaced them with no desired effect:oAlan Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted February 22, 2011 Share Posted February 22, 2011 All as you stated. Checking back thru my records shows I have not yet replaced the MAP sensor, and I believe the ECU takes an initial reading while cranking. My Chilton's book does detail testing the MAP, so I will check that next. If it checks out, I am stumped, so I will hope for a failing MAP. More to follow, and thanks for your response and any ideas. Link to comment Share on other sites More sharing options...
Guest pizzaman7880 Posted February 22, 2011 Share Posted February 22, 2011 have you checked your fuel pump pressure? Your hard start sounds like the problem I had. My fuel pump didn't put out enough pressure to charge the fuel rail but once it started was enough to keep it running..Easy test and sometlhing to eliminate. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted February 24, 2011 Share Posted February 24, 2011 Fuel pressure right on. Have replaced pump, tank, filter, injectors, regulator, hoses. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 4, 2011 Share Posted March 4, 2011 Just checked the MAP sensor, and found it was showing about 4.5 volts, KOEO from the green/red signal wire to ground and sucking on the vacuum hose as hard as I could (experience tells this is at least 20 inches) moved the voltage only 1 volt or so and not smooth. Replaced MAP and car started poorly at first, probably due to fouled plugs, but then smoothed out and started much better several times. Took car for warm up spin and upon return seems to start fine with no pedal. Crossing my fingers and thinking its fixed. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 10, 2011 Share Posted March 10, 2011 (edited) Well fudge, the car failed to start again after sitting 2 days. Cranks fine but will not start. I will check fuel pressure again although it is a real pita since Chrysler in their infinite wisdom elected not to include a test port on the fuel rail. Have read other posts describing similar faults caused by the optical pickup in the distributor. Is there any way to test this part? Does this fail often? Car runs fine after starting, but when it fails, it can be warmed engine or cold. Driver reports that on prior failures he has been able to get it to start by pounding the gas pedal repeatedly while cranking, but this time even that would not work. Please note I have replaced TPS, IAC coolant temp sensor, MAP, coil wires cap and rotor, fuel pump, regulator, filter and rebuilt entire engine and trans. Car runs great but continues to have this intermittent starting failure. I will try to start with TPS unplugged tomorrow PM just for grins as just because its new doesn't mean its not faulty, but this thing is getting my anger level dangerously high. Help! Just thought some more about how the ignition works on these beasts and remembered the ECU is looking for a distributor signal to locate TDC before it will fire the ASD and Fuel relays. I have not changed the ASD relay and as relays are quite prone to intermittent failures, this could be the culprit. Anyone have experience with this part? Edited March 10, 2011 by rustfarmer more ideas (see edit history) Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 12, 2011 Share Posted March 12, 2011 I checked the car Thursday PM and did my usual start up routine which is to turn key to on and let the fuel pump run until it builds up pressure and stops running. Presto, car started pretty well. Turned off and started again fine. I have advised the driver to use this procedure, especially if the car hasn't been run for a day or two. I may replace the in tank fuel pump (again) if he has more trouble with this, as I have seen many new pumps perform below spec's, but for now we'll see how he does. Thanks for those who have helped. Link to comment Share on other sites More sharing options...
Guest pizzaman7880 Posted March 12, 2011 Share Posted March 12, 2011 It may not be the pump. The fuel pressure regulator on the fuel rail is supposed to keep fuel in the rail. It may be leaking back into the tank and this is why you have to wait for the fuel pump to pressurize the system. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 12, 2011 Share Posted March 12, 2011 Thanks for that idea. The regulator was replaced, and thou it could be bad anyway, fuel pressure test seem to indicate its not leaking back enough to show on a normal test. It is possible that a very small system leak (regulator, pump or even injector) could cause these symptoms. Can you leave yours sitting 3 days and jump right in and fire it up without letting the pump run up before cranking? Link to comment Share on other sites More sharing options...
TwinCamFan Posted March 13, 2011 Share Posted March 13, 2011 The ECU is programmed for a '2 second burst' to run the fuel pump when the key is cycled on regardless of pressure. It could be at zero or full pressure, the pump will still run. It wonn't run again until the ECU sees rotation of the motor (Via the distributor pick up plate ie Hall Effect Switch)Alan Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 13, 2011 Share Posted March 13, 2011 This is interesting in that my car does not seem to operate in this fashion. On first cold start the pump will run 5 to 9 seconds depending on how long it has been sitting since last start. If run and then shut down and left for 3 or 4 minutes, the pump will run only very briefly (perhaps 2 seconds) and car will start. If on first cold start one does not wait for pump to finish running and kick off, car will not start or will be very difficult to start. Also note: car has optical type distributor. Link to comment Share on other sites More sharing options...
TwinCamFan Posted March 14, 2011 Share Posted March 14, 2011 So are you saying you've narrowed this down to solely a fuel pressure issue? Try this, run a 12V 'jumper' wire to the + side of the coil, this bypasses the ASD relay and runs the pump the whole time the voltage is applied. Obviously not a permanant fix but it can help with the diagnosis.AlanPS, are you certain you are not hearing the ABS pump running for 9 seconds:confused:? Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 14, 2011 Share Posted March 14, 2011 I'm not certain of anything these days, but if I'm hearing the ABS pump it seems to be located in the fuel tank area, lol. I also am not certain the issue is fuel pressure, just a guess based on the symptoms. That is what got me started on the ASD relay as a possible fault. As you are aware, intermittent problems can be tough as they never fail when you want them to. Are you saying to try a jumper from battery + to coil + and this will backfeed the fuel pump as well as eliminating the ASD relay? Link to comment Share on other sites More sharing options...
Guest pizzaman7880 Posted March 15, 2011 Share Posted March 15, 2011 Rust --I just went out and started up the 91. Put the key in and turned it on and it started right up. I did not wait to hear if the fuel pump ran. It has been at least 8 weeks since I last started it up. The 91 has new fuel pump, fuel regulator, new fuel filter, new O rings on the injectors and all new hoses and clamps. Link to comment Share on other sites More sharing options...
TwinCamFan Posted March 15, 2011 Share Posted March 15, 2011 I'm not certain of anything these days, but if I'm hearing the ABS pump it seems to be located in the fuel tank area, lol. I also am not certain the issue is fuel pressure, just a guess based on the symptoms. That is what got me started on the ASD relay as a possible fault. As you are aware, intermittent problems can be tough as they never fail when you want them to. Are you saying to try a jumper from battery + to coil + and this will backfeed the fuel pump as well as eliminating the ASD relay?Yes:cool: Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted March 20, 2011 Share Posted March 20, 2011 Cool beans. I'll try this at next opportunity. Thanks. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted April 30, 2011 Share Posted April 30, 2011 So now the car will only start if I try three or more times to crank, but once started runs fine. Guess I'll bite the bullet and hook up the (PITA) fuel pressure gauge again to see what's up. After replacing the whole tank, pump, filter, regulator, injectors and all rubber lines you might think I would have fixed this problem, but not so. I wish I had never heard of these odd ball cars. They drive like crap being front wheel drive and ride very harsh. This ones going to the crusher soon if I can't find the problem. Total rebuild and all I have is heartache. Link to comment Share on other sites More sharing options...
ironmike4134 Posted September 6, 2011 Share Posted September 6, 2011 To twin cam fan.. or anyone else? You posted "...run a 12V 'jumper' wire to the + side of the coil, this bypasses the ASD relay "....What do you do with the negative side? Ground it or go back into the plug? I am trying to bypass the ASD... I have fuel pressure, but now no spark... Link to comment Share on other sites More sharing options...
TheLanesinNY Posted September 6, 2011 Share Posted September 6, 2011 By jumper he is referring to a clip lead or a piece of wire. This 12 Volt positive bypasses the ASD relay. Once drove an 85 turbo dodge around that way a week or two since the power box (now built into the SMEC/SBEC) had failed. Of course this removes an important safety feature built into the auto, which would shut off the injectors, fuel pump and ignition once the engine stops turning. You don't need to ground anything, this method uses all the normal returns.In reference to the person about to throw in the towel, this is why i always recommend test first, don't replace until you locate the failure, other wise you sometimes replace a lot of parts but the problem only gets worse from disturbing connections, lines and other items. (Unless you are doing a full restoration, in which case it's not really the same car.)-Rich Link to comment Share on other sites More sharing options...
Guest george w Posted January 22, 2012 Share Posted January 22, 2012 I know I'm late to the party on this one but I suspect a problem with the check valve in the fuel pump. The fuel pressure regulator does not hold fuel pressure in the system, the check valve in the fuel pump does. The system should build and hold fuel pressure when first cranking the engine, but keep in mind that the pump shuts down in a few seconds until the engine actually starts. If the check valve doesn't hold pressure the car won't start properly because there's not enough residual fuel pressure to operate the injectors and the pump's not running anymore. I also suspect that there's also some fuel line drain back for the same reason. "Pumping" the gas pedal should have nothing to do with this.The jumper test to keep the pump running ought to confirm this diagnosis. Link to comment Share on other sites More sharing options...
Guest rustfarmer Posted January 22, 2012 Share Posted January 22, 2012 Please note I used a fuel pressure test gauge to confirm pressure remains after shut down. I recalled that the fuel pump I purchased did not come complete with the check valve, so I obtained a better brand unit which came as a complete module and now problem is solved! It is interesting that the gauge revealed only a very slow drop in pressure after shut down which some posters assured me is normal, however, now the car starts well even after sitting 7 days or more. The lesson seems to be (based upon other experience as well) that replacement fuel pumps should not be chosen on price alone. I have have best luck with Delphi, or the dealer part. Link to comment Share on other sites More sharing options...
Guest george w Posted January 22, 2012 Share Posted January 22, 2012 Thanks for confirming the diagnosis. This is issue likely to pertain to all the Chrysler products of this era in general and for sure all those models, which are many, that use this same engine. Link to comment Share on other sites More sharing options...
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