Matt Posted June 3, 2005 Author Report Share Posted June 3, 2005 Well since the problem started after I fueled up this past Tuesday I'm going to hope it is bad fuel. The engine does the same thing with the new PCM and the old PCM. Yesterday, Thursday, I put in a new fuel filter and a can of dry gas. This Am the tank was just below 1/4 full so I put in $25.00 of mobile Hi test 93 Oct. I was useing that all along but decided to try the Sunoco. Lets see what happens now. I cant see buying the new PCM just yet, I can't believe I have another bad PCM. I tryed to figure out how I could get my hands on the new PCM and test it and if it does the same thing try and return it saying I did not use it. It may come in a sealed package or something. I will just have to wait for the Mobil gas to kick in. Later... Link to comment Share on other sites More sharing options...
Matt Posted June 4, 2005 Author Report Share Posted June 4, 2005 I took some very good advice and replaced the PCM. I most likely would have any way. The original one definetely went bad so I bought a used one. A new problem came up with intermitendt rough idle at idle and what felt like fuel starvation under exceleration. I used both PCMs I had here to test against each other to isolate the new problem. The problem showed up with both PCMs. So that did not work!! This AM on way to work the same engine problem came up. ""When I got to work I called my parts shop and had a new PCM delivered"". The engine ran good after work wile rideing around testing it. I stoped for lunch and went out again. Then the same problem came up again. I was so mad, ya all have no idea. I pulled over and ran the PCM Diagnostic codes and this time " I got codes" The last few days when the problem was happening I either was to late or there were just no trouble codes. Today I got these codes. PO32 -PO34 and PO71. With my Diagnostic code book for this year car I checked the codes. They are "open map sensor signal" " map sensor signal to hi" " intermittent map sensor signal". My guess is the map sensor has a problem. DAH!! The not so funny part of this is when I checked it by taking it off and looked at it, on the bottom it says Made in Hong Kong. The new Map Sensor I got from Napa and put on the old engine did not have that on the bottom. When I gave the place that was swaping engines for me a" Box O Parts" I told them the the Map Sensor on the old engine is a week old, as are many other parts, so put it on the new engine. They did not. Yet another (**** **) on there part. So in a little wile I'm off to napa to buy a new Map Sensor. There is no use in calling the shop that did the job. If they could not even hold on to my old engine that I said I wanted parts from I'm sure they do not have that sensor. They said they lost the engine so there is no hope for the sensor. I will report back later if it works... Link to comment Share on other sites More sharing options...
Scotty Posted June 4, 2005 Report Share Posted June 4, 2005 ITs possible that the PCM wasn't right for your car and was not showing codes... My gut tells me that it was good to replace the PCM... You are getting close Matt, better sell it as soon as you get it running good! j/k Link to comment Share on other sites More sharing options...
Matt Posted June 4, 2005 Author Report Share Posted June 4, 2005 I learned a lesson, though I will look the fool I will share it with all so maybe someone will learn. If wile trouble shooting you remove the plug from the Map Sensor and then the vacume hose wile the engine is runing it will show trouble codes on the PCM. Then like me you will be fooled into thinking you have found a problem device. I'm glad I realized what I did before buying a new Map Sensor. Well Mike it was good to put in a new PCM anyway. The other one was at least 12 years old. I just spent hours going over everything under the hood. Boy it's hot under there at 220 deg. I'm beet. I rechecked engine timing, all electric plugs and cleaned the ones to the Distributor. I looked at all vacume lines and checked all spark plug wires,cap and rotor. I had it idleing with AC on and off for at least long enough for the problem to kick in AND it did not. But sure as rain it will act up if I take it for a ride. I like this car very much Mike, I would like to not have to sell it if I can help it. The engine was perfect for so long, then this past tuesday at 6:50PM it began to idle rough and then almost shut down for about 90 seconds and then it cleared up for a wile. Now it does it now nod then. Since I put in this New PCM it is not as bad but not right. Time to shower, eat and relax. I'm beet.. Link to comment Share on other sites More sharing options...
Scotty Posted June 4, 2005 Report Share Posted June 4, 2005 Did you check fuel pressure. Carry the fuel pressure guage with you and when it happens check the fuel pressure. Have you used any injector cleaner? As you know its a no-no. Did you say there was an aftermarket coil on it (Accel).. Look for carbon tracks in the cap and take a look at the rotor and contacts in the cap.. I just threw out a coil for the 4.9 a few months ago too bad. Let us know how this pans out when you drive it.. Link to comment Share on other sites More sharing options...
Matt Posted June 4, 2005 Author Report Share Posted June 4, 2005 I just want to note that the "Vehicle diagnostic System" booklet I have is very nice to have. I used it today to trouble shoot the rough runing problem. In the PCM mode I was able to check the Parameters from #s PD01 to PD99. Wile it was acting up every parameter was with in the book range. Also when first entering PCM diagnostic mode there are no codes showing any problems. It has been very difficult to find the cause of the intermitent rough runing. Also when checking things that there are two of like the-front and rear injector banks and the front and rear oxygen sensors the parameter ranges have been almost equal. This I think rules out one device being bad when parameters are equal for both. With my limited knowledge there is not much more I can do to find the cause of this problem. I can not find a reason that makes the engine begin to shake and miss, then if you race it a bit it will clear up. Some times it is not to bad and others it last a little longer. PCM is new today and everything else is new and or in working order.Aprox 60.000 on engine. Fuel pressure is good,35 at idle and about 39 PSI or so when reving slightly ( Guru ware are you) What am I missing guys?? Link to comment Share on other sites More sharing options...
Matt Posted June 4, 2005 Author Report Share Posted June 4, 2005 Hi Mike, no injector cleaner used at all. Cap and rotor all look good. The coil was what came with the distributor I got from Scott when he sent a replacement for the bent one. The coil looked like new. Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Ranger what have I missed??? Can you think of anything? Mike has good idea, maybe coil? Holy crap- I just remembered, I have a spare coil in tool box from old distributor. Be back in a wile..... Link to comment Share on other sites More sharing options...
Ranger Posted June 5, 2005 Report Share Posted June 5, 2005 Matt, An intermittent coil break down could surely cause what you are expiriencing. I would also do what Mike suggested except I would put that fuel pressure guage on and tape it to the windshield and leave it there til the problem rears it's ugly head. That way you can check the fuel pressure as it happens. Maybe just a burnt wire on the fuel pump causin it to go intermittent. Other than that I am at a loss. I will bet though, when it is figured out we are all going to be slapping our foreheads and saying, "Now why didn't I think of that? It was so obvious". Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Ok, I just got back from swaping the coil. I forgot I had a spare from the originial distributor. I also took it out for a test ride. It started out good, a nice smooth idle and very powerful rocket ship excelerations. It spins the tires very easy. It had no problems at a few stop signs and a couple of lights. I headed back through town and then at a red light at idle the engine began to shake a little, you can even see it in the tach. Then green light and press on the excelerator and "nothing". The tack drops and it sputters, I press up and down on the excelerator, it bucks and then comes back to life. After that it was back to being perfect again all the way home. I found no codes on the PCM. This has got to be a bad dream, I can't figure this out. I'm going crazy. Link to comment Share on other sites More sharing options...
Scotty Posted June 5, 2005 Report Share Posted June 5, 2005 Matt, take an ohm meter and test each ignition wire and post the results here if you can, maybe you have a bad wire or cracked plug insulation.. Try spritzing the ignition wires to see if you can induce the stumble Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Hey Mike, the plugs and wires are new Delcos. But I will try to do the Ohm test ASAP. I just filled a spray bottle with water and am going out side now to spray the wires and cap down. Be right back... Link to comment Share on other sites More sharing options...
KevinW Posted June 5, 2005 Report Share Posted June 5, 2005 Have you checked/cleaned the various ground connections (near the starter and the cross-member near the radiator, passenger side come to mind)? ___________________________________________________ Link to comment Share on other sites More sharing options...
Scotty Posted June 5, 2005 Report Share Posted June 5, 2005 Have you checked/cleaned the various ground connections (near the starter and the cross-member near the radiator, passenger side come to mind)? Good Idea Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Well I just soaked the wires and surrounding areas down along with the distributor cap and could not make it idle rough. I then shut the lights so it was pitch black and could see NO sparking or arcing any ware. What is this about ground wires? How could a ground wire give me this problem? Are these ground wires I'm supposed to look for wide straps bolted to the engine to frame? What should they look like and ware exactly should they be? Link to comment Share on other sites More sharing options...
Ranger Posted June 5, 2005 Report Share Posted June 5, 2005 Have you checked the contacts inside the cap for spark erossion? Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Yes Ranger I did. Everything is brand new too. So it is all looking like new yet. There has to be a reason for this problem. Link to comment Share on other sites More sharing options...
Ranger Posted June 5, 2005 Report Share Posted June 5, 2005 Ok, then I would install the fuel pressure guage to the windshield to either eliminate or incriminate the fuel pump. Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 I wish I would have brought it home with me. It's locked in my tool box at work. It was Wednesday that I checked fuel pressure and the guage also has a button to push to let fuel out. The pressure was about 35 at idle and 39 or 40 at a slightly higher RPM. I did not check it when the problem was going on,That will be next. I will tape it on the window Monday. I also drained out fuel in a glass jar to check for water. There was none. On I think Thursday I changed the fuel filter under the frame and put in a can of dry gas. Thanks for the help, things like this bug the hell out of me. I do not stop till I figure these things out. I'v been up since 5:30, had to work 1/2 day today and then I been on the car since 1 PM till now. I'm going to sleep in about 15. Catch ya later. O, Sunday I'm driving the car up to my parents for a short visit, about 45 min away on thrughway. I'm going to put more fuel in too. This should be very interesting. Catch ya later, have a good night.. Link to comment Share on other sites More sharing options...
KevinW Posted June 5, 2005 Report Share Posted June 5, 2005 What is this about ground wires? How could a ground wire give me this problem? Are these ground wires I'm supposed to look for wide straps bolted to the engine to frame? What should they look like and ware exactly should they be? The Jekyll/Hyde character of your problem suggests it is electrical in nature. A high resistance ground connection may affect one or more PCM inputs - garbage-in, garbage out. I recall reading a TSB that outlined how these grounds may be responsible for an intermittent rough running or stalling condition on the 4.9. Since these grounds are part of the PCM wiring harness, I would expect they're ~18 gauge wire with black insulation. ___________________________________________________ Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 I will say that the way it cuts in and out it sure feels like electrical. I even had a day last week that the fuel guage was all messed up. I just" fueled up" and the guage went down to E and I shut the car and restarted and it "jumped up in 1/8 increments" back up to my almost full mark. Even this Am on the way to work it was not reading correct, it was up and down during the ride. The fuel guage is working good now since I replaced the PCM this AM.Hmm, could there be a bad wire on one of the packs that plug into the PCM? I will have to look them over good in the AM. What you read is sure interesting to me. You know I have the PCM on the floor but just thinking about it and the way it mounts it is not grounded. I guess it does not have to be. So there must be a diagram someware that shows all the ground locations. I need to go over all of this stuff. This all started last Tuesday evening. Up to then it was so perfect, I was in love with the car. It came about so suddenly, like someone turned off a switch. Could a ground wire have broken someware??? I need to know ware the grounds are and look over the PCM wires. I wish it were light out. Just as well, I need some sleep. Thanks so much for your help. I must say this, if any one has info on the ground wire locations and pics it will be Mike. He is so good with parts brake downs. Well I will catch ya later. I need rest.... Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Good Sunday Morning to all. I'm going to start searching for bad ground wires today. If any body has any diagrams of ware the ground wires should be on a 93 Seville please let me know. I will look at the 3 packs of wires good going to the PCM also. Link to comment Share on other sites More sharing options...
Scotty Posted June 5, 2005 Report Share Posted June 5, 2005 Matt, you need a diagram like this for your 93, this is from a 92.... If you have a manual you should find it in your manual in the electrical section. I would start with your equivalent of G301 and G305 at the RH kick panel also check and clean G100. Look at the PCM connectors in the wire harness for corrosion or burned contacts. I am off to Brooklyn, speak to you later Link to comment Share on other sites More sharing options...
Matt Posted June 5, 2005 Author Report Share Posted June 5, 2005 Thanks Mike. I will use this info to start my looking today and Monday I wil call Frank from B. andget him to fax me a 93 Seville Diagram. Have a good trip Buddy. Catch ya later. Matt P/S If any one here has a 93 Seville Ground Diagram and can send it That would help very much . Thanks Link to comment Share on other sites More sharing options...
KHE Posted June 5, 2005 Report Share Posted June 5, 2005 I would think that a '92 Seville and a '93 Seville (Non-STS) would be very similar if not identical as far as service documentation. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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