Help! At my wits end...
Thread Starter
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
Purchased a fuel pressure gauge today.
With the key on / engine off I am getting a reading of 41 PSI
With the engine idling I am getting a reading of 43 PSI
Both of those readings are with the vacuum line to the fuel pressure regulator unhooked.
With the FPR vacuum line hooked up and idling I am getting a reading of 36 PSI.
This was cold so I still need to do a warm test but I think its safe to say that fuel pressure most likely isn't a problem. The pressure also did not bleed off at all really once the car was turned off. It maybe took 5 minutes for it to drop a pound.
With the key on / engine off I am getting a reading of 41 PSI
With the engine idling I am getting a reading of 43 PSI
Both of those readings are with the vacuum line to the fuel pressure regulator unhooked.
With the FPR vacuum line hooked up and idling I am getting a reading of 36 PSI.
This was cold so I still need to do a warm test but I think its safe to say that fuel pressure most likely isn't a problem. The pressure also did not bleed off at all really once the car was turned off. It maybe took 5 minutes for it to drop a pound.
Last edited by TorchTarga94; Dec 2, 2013 at 09:07 PM.
Melting Slicks
Joined: May 2010
Posts: 2,082
Likes: 3
From: Conowingo Maryland
were these fuel pressure reading when the car would not start? they mean nothing unless the car will not start. these fule pumps love to crap out when hot and shut off then after the cool for a while they work fine
Thread Starter
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
I won't really have the time to do a proper warm test until the weekend, but I will make sure to do that. Can the fuel pump really get that warm? Its at the rear of the car away from anything really hot.
Racer
Joined: Mar 2013
Posts: 253
Likes: 12
From: Ogden Utah
Yes it can get warm if it is drawing lots of amps but I think the car would just die and not have the warm start problem. I am way more incline to believe electrical. I could be wrong about a sensor but it just my way of looking at it.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I'm betting against the fuel pump. One thing I'd do is take the new ICM back where I bought it and have them test it...make sure they run it through at least ten cycles though...most guys think 4-5 cycles is enough, but their mistaken.
I can't really say this about your 94, because mines an 87 l98, but one of the tell tale signs of a ECM going bad is similar...they shut down because there getting (the ECM) hot frequently, unfortunately we can't really test an ECM, neither can a parts house. But I think some of the guys on the forum in the past used something to keep it cool for test purposes. Hopefully someone will chime in.
I can't really say this about your 94, because mines an 87 l98, but one of the tell tale signs of a ECM going bad is similar...they shut down because there getting (the ECM) hot frequently, unfortunately we can't really test an ECM, neither can a parts house. But I think some of the guys on the forum in the past used something to keep it cool for test purposes. Hopefully someone will chime in.
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Thread Starter
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
Thanks everyone for all of the input. After no luck testing various sensors and fuel pressure, it seems it was the Optispark. This time I went with a new Delphi unit, loctited the rotor screws, and sealed the cap with black RTV. Have not been able to replicate the issue I was having.
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Hopefully it was the OptiSpark, but I would not be surprised to read that the problem reappears.
This sounds more like a PCM failing when hot, possibly the ICM or the ignition coil.
Time will tell......
This sounds more like a PCM failing when hot, possibly the ICM or the ignition coil.
Time will tell......
Thread Starter
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
Gee thanks for the kind words of encouragement!
I kid. I wouldn't be surprised either, this car does whatever it wants. I really did my best trying to diagnose it but I can really only do so much with an intermittent problem like this. Used freeze spray on a bunch of sensors to try and isolate what the problem was. Sometimes it would fire up even after driving the car very hard for 10 to 15 minutes at a time. I don't know I have been having this problem ever since I changed the optispark with a cheap cardone unit from Advanced. The thing is is sometimes it would only does it once a month.
As you said, only time will tell. And so will my patience, it sucks trying to diagnose electrical problems and work on the car more than I get to drive it. I really don't even drive it hard for fear of breaking something else which really takes the fun out of it. I don't drive it a lot though, or try to. I'd just like it to be somewhat reliable. I understand it's an older car but this ignition system was a horrible, Horrible design.
I kid. I wouldn't be surprised either, this car does whatever it wants. I really did my best trying to diagnose it but I can really only do so much with an intermittent problem like this. Used freeze spray on a bunch of sensors to try and isolate what the problem was. Sometimes it would fire up even after driving the car very hard for 10 to 15 minutes at a time. I don't know I have been having this problem ever since I changed the optispark with a cheap cardone unit from Advanced. The thing is is sometimes it would only does it once a month.
As you said, only time will tell. And so will my patience, it sucks trying to diagnose electrical problems and work on the car more than I get to drive it. I really don't even drive it hard for fear of breaking something else which really takes the fun out of it. I don't drive it a lot though, or try to. I'd just like it to be somewhat reliable. I understand it's an older car but this ignition system was a horrible, Horrible design.
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
i was using a new cardone opti on my car. the first one lasted the longest at just over 2000 miles. after the second one failed at 500 miles my store wouldn't give me my money back, however they gave me a full refund in store credit. Interestingly enough you can get the MSD vented cap conversion and a MSD coil for almost the cost of hat cardone opti, so i used my store credit to get that for my '93. i found a NOS GM opti for my car. I'm curious though, does the Delphi opti for the earlier cars have a Mitsubishi sensor?
Racer
Joined: Mar 2013
Posts: 253
Likes: 12
From: Ogden Utah
Drive it like you stole it! have fun with it. It is designed to be driven. I drive mind like the sports car it is. they do require some tinkering but I look at it as part of the experience.
I have worked a lot on mine, but now I just drive it. There is an alternate ignition out there LTCC. Question for you , If I may.
Have you taken that cardone opti apart? just curious see if there is something blatantly wrong with it.
I have worked a lot on mine, but now I just drive it. There is an alternate ignition out there LTCC. Question for you , If I may.
Have you taken that cardone opti apart? just curious see if there is something blatantly wrong with it.
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
Drive it like you stole it! have fun with it. It is designed to be driven. I drive mind like the sports car it is. they do require some tinkering but I look at it as part of the experience.
I have worked a lot on mine, but now I just drive it. There is an alternate ignition out there LTCC. Question for you , If I may.
Have you taken that cardone opti apart? just curious see if there is something blatantly wrong with it.
I have worked a lot on mine, but now I just drive it. There is an alternate ignition out there LTCC. Question for you , If I may.
Have you taken that cardone opti apart? just curious see if there is something blatantly wrong with it.
Thread Starter
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
Giamanut- no I haven't taken the cardone apart. It has a lifetime warranty so I am going to try and return it for a refund since it looks like it crapped out after only 6 months. The one thing about the LTCC conversion is you still have to leave the opti hooked up to send a signal to the PCM. So you don't completely eliminate it. You do eliminate the distributor part of it though.
Eatmydst - What symptoms were you experiencing with your cardone units? Interesting you went through 2 of them, something must not be right inside of them. I am not 100% sure if the Delphi unit I installed uses a Mitsu sensor. I didn't delve that far into it. I do know Delphi built the opti for AC Delco during production. AC Delco just slapped their own part number on it. I have heard the Delphi units still use the Mitsu sensor but that doesn't confirm anything. It definitely seemed better built than the Cardone. Even the splines on the drive shaft looks better.
Eatmydst - What symptoms were you experiencing with your cardone units? Interesting you went through 2 of them, something must not be right inside of them. I am not 100% sure if the Delphi unit I installed uses a Mitsu sensor. I didn't delve that far into it. I do know Delphi built the opti for AC Delco during production. AC Delco just slapped their own part number on it. I have heard the Delphi units still use the Mitsu sensor but that doesn't confirm anything. It definitely seemed better built than the Cardone. Even the splines on the drive shaft looks better.
Last edited by TorchTarga94; Dec 10, 2013 at 05:32 AM.
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
Giamanut- no I haven't taken the cardone apart. It has a lifetime warranty so I am going to try and return it for a refund since it looks like it crapped out after only 6 months. The one thing about the LTCC conversion is you still have to leave the opti hooked up to send a signal to the PCM. So you don't completely eliminate it. You do eliminate the distributor part of it though.
Eatmydst - What symptoms were you experiencing with your cardone units? Interesting you went through 2 of them, something must not be right inside of them. I am not 100% sure if the Delphi unit I installed uses a Mitsu sensor. I didn't delve that far into it. I do know Delphi built the opti for AC Delco during production. AC Delco just slapped their own part number on it. I have heard the Delphi units still use the Mitsu sensor but that doesn't confirm anything. It definitely seemed better built than the Cardone. Even the splines on the drive shaft looks better.
Eatmydst - What symptoms were you experiencing with your cardone units? Interesting you went through 2 of them, something must not be right inside of them. I am not 100% sure if the Delphi unit I installed uses a Mitsu sensor. I didn't delve that far into it. I do know Delphi built the opti for AC Delco during production. AC Delco just slapped their own part number on it. I have heard the Delphi units still use the Mitsu sensor but that doesn't confirm anything. It definitely seemed better built than the Cardone. Even the splines on the drive shaft looks better.
Thread Starter
Melting Slicks
Joined: Jul 2011
Posts: 2,605
Likes: 202
From: Trinity FL
The both of the cardone opti's failed in the same way. After car got to temp it would be running fine, then out of no where the temps would climb abnormally fast, we're talking from 193-225 in a matter of minutes, even with the cooling fans on high. When it hit 225 the tach would start dancing around and the car, would start shut down. Wouldn't start again until car cold down. Did all the test and failure was in the optical side of the opti. The only thing I can figure was that it wasn't controlling timing correctly which caused car to hear up fast. Now with the GM opti the car, is back to normal.