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Discussion Starter · #1 ·
I have an LT1/T56 in a 74 Nova that I have been working on. I haven't been online here for awhile. I'm having a few problems with the engine. The got the car running with a stock harness I modified. I ended up purchasing a stand alone harness from PSI. The car runs but has trouble idling some times. Sometimes it will idle/run perfect, then the idle will change and it will die. Any ideas?

Also I'm having trouble with the water temp. I wired my fans up to be controlled by the computer. The computer has also been flashed to remove VATS, etc. My temperature will get well over 200 degrees and my fans will only come on part of the time. I installed a new thermostat and water pump when I put the engine in. I'm not sure if the thermostat is sticking or why the engine keeps getting hot. The radiator is the stock aluminum radiator from the LT1 Camaro. Any ideas on this subject? I can provide more details if needed. Thanks!
 

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Has the motor been modified to make more power? If so it could overwhelm the stock radiator. Otherwise your problem is going to be sensor related (I would look at the oxygen sensor first to see if it is working as it sounds like it is pushing the engine lean to compensate for something the computer sees from one of the many sensors on the car).

Big Dave
 

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The LT1 in our 94 Firebird does not run the fans until the engine temp is 230° and then only the larger one. Running the AC causes the fans to run regardless of temperature. If you can not reprogram the start up temp then using a sensor in the head and a relay will work to turn them on at a lower temp.
 

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Discussion Starter · #4 ·
Has the motor been modified to make more power? If so it could overwhelm the stock radiator. Otherwise your problem is going to be sensor related (I would look at the oxygen sensor first to see if it is working as it sounds like it is pushing the engine lean to compensate for something the computer sees from one of the many sensors on the car).

Big Dave
Dave thanks for the reply. The engine is almost completely stock to my knowledge. Once I got it running I'm not positive that the cam is stock. It has more of a lope than other stock LT1s that I have heard run. I will look into getting new o2 sensors if fixing the fans doesn't help!

The LT1 in our 94 Firebird does not run the fans until the engine temp is 230° and then only the larger one. Running the AC causes the fans to run regardless of temperature. If you can not reprogram the start up temp then using a sensor in the head and a relay will work to turn them on at a lower temp.
Thanks for the reply Phillip. I contacted Brendan who reprogrammed my computer and he said he set it up for the first fan to come on at 180 and for them to go off at 178. He also remined me that the computer supplies a ground signal so I might have them wired up wrong. I'm going to look into that a little closer.
 

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Discussion Starter · #5 ·
I hooked up a test light to the signal wire from the computer (which supplies a ground). The fans kick on around 180, however, the temp goes up a little more and the fans go back off. So for now, I unhooked the signal wires and wired in a toggle to turn the fans on. The engine isn't getting hot anymore. However, It still won't run right. The check engine light doesn't come on unless it idles really slow. Then it will go back off. I'm thinking it could be a throttle position sensor or something faulty. It seems the computer doesn't know where the throttle plate is. I can open and close the throttle quickly and it will cut out with almost no response. Any ideas? Suggestions?
 

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Best guy I know that specializes in EFI hot rods lives in Huston, Texas. If you where willing to go for an interstate drive I could tell you how to contact him.

Just to be different he built his own W-30 Olds Cutlass out of a junk yard late seventies body by using a 425 block out of a Riviera to build a 455 (with aluminum heads) and then bolted on his own home made brackets and belts to support a centripetal blower to get 15 pounds of boost. Guy is a master machinist (makes all of his parts out of billet stock); welder (fabricated his own frame for the car back-halved with home made four link and a complete custom front end using tubular A-arms on coil overs and rack and pinion steering that he made from scratch and fabed up); and paint and body man (made all of his own W-30 hang ons to convert an ugly late seventies stocker, lost the offensive big baby bumpers and went with a full floor pan rolled into the front grill): in addition to being a professional mechanic with his own shop.

Big Dave
 

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Discussion Starter · #8 ·
I haven't worked on the car in awhile. I bought a house so I have been busy moving and everything. I have a code reader now and I plan on seeing what it says. I'll will post as soon as I figure something out. Thanks for all the suggestions so far.
 

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210 F is a normal operating temperature for newer fuel injected cars. It sounds like your engine is right where it needs to be.
 
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