my project is choking, and i dyno friday. HELP!
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From: Bellingham, WA
my project is choking, and i dyno friday. HELP! this is my first post! my car is a 1986 Mazda RX-7 with a 1994 LT1/T56 swapped into it, though i am not sure if you guys are cool with doing that to an RX-7. check it out HERE if you like a good read, click on 'view'. anyway, i got my project running last wednesday and it ran really sweet for a whole week so i figured it was time for a dyno to have some bragging rights. but tonight i began having a few problems.
i was taking the brother in law for a spirited drive and it hesitated a few times on acceleration, like a break in the fuel flow. then on the way back the car completely stalled on me, and it wouldn't start back up. i checked the wiring for about 5 minutes and gave it another try, it started up agian, but was running like crap... sputtering, coughing, clunking, and stalling. so we went back to get a truck to tow it back. when we got back, i gave it another try, and it ran perfect for the rest of the night. the temp gauge, oil pressure gauge, and volt meter were all in normal operating range when this all happened.
does anyone have any advice for me considering i have a dyno appointment friday? i am pretty sure it was fuel related, but not 100% sure, maybe it was the optispark?. i was thinking that a good injector cleaning and a fuel filter replacement would be a decent start considering that filter came with the car and is probably pretty old. maybe it's the lack of O2 sensors? what are the signs of a bad optisparK? any help is appreciated!
i was taking the brother in law for a spirited drive and it hesitated a few times on acceleration, like a break in the fuel flow. then on the way back the car completely stalled on me, and it wouldn't start back up. i checked the wiring for about 5 minutes and gave it another try, it started up agian, but was running like crap... sputtering, coughing, clunking, and stalling. so we went back to get a truck to tow it back. when we got back, i gave it another try, and it ran perfect for the rest of the night. the temp gauge, oil pressure gauge, and volt meter were all in normal operating range when this all happened.
does anyone have any advice for me considering i have a dyno appointment friday? i am pretty sure it was fuel related, but not 100% sure, maybe it was the optispark?. i was thinking that a good injector cleaning and a fuel filter replacement would be a decent start considering that filter came with the car and is probably pretty old. maybe it's the lack of O2 sensors? what are the signs of a bad optisparK? any help is appreciated!
Last edited by mattster03; Sep 1, 2005 at 02:15 AM.
Originally Posted by mattster03
sputtering, coughing, clunking, and stalling.
I always start with the basics,check your manifold vacuum to see if you have any leaks.
Check your wires and coil resistance.
Check the fuel pressure
If its not one of those three start checking sensors.
Check your wires and coil resistance.
Check the fuel pressure
If its not one of those three start checking sensors.
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thanks for the replys. i replaced the fuel filter today, and cut open the old to see what it looked like. it seems it may have been as old as the 20 year old car, pure black. i sense this may have be the root of the problem, i will keep you all updated.
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From: Clarksville,Tn
Originally Posted by mattster03
maybe it's the lack of O2 sensors?
i think it will go to "limp home" mode without o2 feedback, which is open loop...but its not hard to put in 02 bungs in your exhaust...5 bucks a piece and if you cant weld, a muffler shop could do it in no time
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i installed an O2 sensor last night at about 10:00, hopefully that'll help with my dyno today. i am kinda confused because i was under the impressioin that the 94 LT1 only had 1 O2 sensor? but i see a left and a right harness for O2 sensors, though the stock headers had only 1 sensor, the drivers side was factory blocked off. i only put one in... is this wrong? any advice?
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From: Clarksville,Tn
94-95 have 2 (OBD1) , 96-97 have 4 (OBD2). You need 2, one on the right side and one on the left, and the factory didn't block one off, the ecm needs both. After you get both installed I would undo the battery for a minute or two to clear any codes in the ecm so it won't be confused anymore.
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well, that post was a day too late, i ran it on the dyno with only one sensor... but the results were still great! check out the printout, here . thanks for all the help, i am pretty sure it was the fuel filter/ O2 combo.
I checked out your cardomain page, Thats a good read man. Great work and impressive dyno numbers. Keep up the good work man, the car will look sick when it is all one color. I may be PM'ing you soon to ask some questions..my friend is considering doing the swap with a Gen 1 SBC.
Kyle
Kyle
Hey Matt,
I too read through your cardomain site, pretty fun. I did a Lt1 swap into a 89 ext cab s-10 and later did the Lt4 conversion, it was a blast.
What's the reason for not running the alternator? having trouble w/ the regulator frying? the feedback wire coming out of the harness needs to have 470 ohms between it and a keyed voltage source. I took two 1k ohm 1/4 watt resistors, twisted them in parallel to drop them down to 500 ohms, soldered them together, cut the feedback wire, soldered them in and never had another trouble.
Good luck w/ your ride when you get back from fall semester!
I too read through your cardomain site, pretty fun. I did a Lt1 swap into a 89 ext cab s-10 and later did the Lt4 conversion, it was a blast.
What's the reason for not running the alternator? having trouble w/ the regulator frying? the feedback wire coming out of the harness needs to have 470 ohms between it and a keyed voltage source. I took two 1k ohm 1/4 watt resistors, twisted them in parallel to drop them down to 500 ohms, soldered them together, cut the feedback wire, soldered them in and never had another trouble.
Good luck w/ your ride when you get back from fall semester!