LT1/LT4 Tech 1993-1997

LT1 running like garbage

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  #31  
Old 08-15-2009, 09:37 PM
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Something stupid is wrong with this car. I'm wondering if it's the computer due to the "failure to communicate" thing we got on 2 different scanners. The car will NOT take the throttle. You can inch it up through the RPM range by tapping the throttle but when you deck it, it jumps to about 3k and struggles to stay alive until you let go. That's when the fuel pump gets quiet and then gets loud.
 
  #32  
Old 08-15-2009, 09:51 PM
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what condition is the fuel pump in? Recently replaced fuel filter?
 
  #33  
Old 08-17-2009, 12:05 PM
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Brand new Walbro 255 fuel pump and brand new FRAM fuel filter, sir. Car ran for an hour yesterday just fine but stumbling a bit at around 3k. Parked it for about and hour or two, went to drive it and it wouldn't take any throttle under a load. Brand new opti, wires and plugs. Help. Is it mass air, TPS, the computer?
 
  #34  
Old 08-17-2009, 01:55 PM
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Here is the sensor tester for ignition mod, tps,O2,map,Maf,knock,cps. I got mine at AutoZone for 50.00 a few yrs ago.

http://www.actron.com/product_detail.php?pid=16163
 
  #35  
Old 08-17-2009, 01:58 PM
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well the maf is cracked so u better get a new one of those to take it out of the picture. have u done the fuel pressure test yet? have u changed the ignition control modual? the tps could do it but i would do the busted maf first.
 
  #36  
Old 08-21-2009, 08:02 AM
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Any update on the car?
 
  #37  
Old 08-21-2009, 02:02 PM
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Last year on my 2002, it started having the same symptoms. The only true difference was mine was throwing codes, and had a "Reduced power" light on. After searching and searching I found out it was all just the TPS.... (or the chip bored that controlled it). It was about $500 for the new bored, and then I had to have the dealership "program" it.... but it ran like a champ right after. I don't know the differences between the 95 and 2002.... but maybe it will help. TPS is my guess on the issue.
 
  #38  
Old 08-21-2009, 02:59 PM
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The fuel pressure test really needs to be done to rule out those parts. If you can rent/borrow a tester, get one with a longer hose and mount it to your wiper arm and drive your car to watch the gauge- PULL YOUR WIPER FUSE(S) FIRST. This is kind of gangster but it works- coat hangers wrapped up are good. Run the hose under hood by cowl and put rags on either side of the hose so it isn't pinched. Also the MAf should be tested or swapped to try. It is very sensitive and if it was cracked I would consider it all done. It is shady but buy one and try it very carefully, and if no good return it! Sounds like a MAF issue but you have to verify fuel pressure to engine under a load condition. At the same time try to get a fuel sample- have you refueled lately? I just drained about 3 gallons of water out of customers BMW from their last fill- and believe me I was running in circles for a while before I found it. Good luck- you CAN fix this car.
 
  #39  
Old 08-24-2009, 11:57 AM
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Did you do any voltage tests on the opti/computer and the ICM? You are going to want to disconnect the test connector and with the car key on use a volt meter and measure the voltage (DC) at terminals A and B of the test connector. You should see a voltage reading between 0.5 volts and 5volts (mine is at 4.8V). If you get anything less that 0.5V or more than 6 volts check the wiring for any shorts. If you have a good reading then disconnect the opti connector and do the same test on terminals A and B there. Any bad voltage readings can be the result of a faulty PCM or shorts/broken wires.

For testing the coil here is a link that explains how to do that. it also includes the diagram of the opti connectors

http://shbox.com/1/4th_gen_tech2.html#opti_test
 
  #40  
Old 08-24-2009, 07:41 PM
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Well as far as I know it goes 2 the last page uve viewed or something unless u press last page but maybe one of the other mods can help u a little bit more. Im not completely sure about this
 


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