dropped in LM7 on Nova, overheating, prolly needs tune?
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dropped in LM7 on Nova, overheating, prolly needs tune? so i just recently swapped to an LM7 5.3
idles great, but it overheats after driving after 20-30 mins,
it goes on "crawl" mode, put it on drive or reverse it wont even move!
new water pump, new radiator, im starting to think it needs a proper tune.
i used painless harness, painless said its plug and play but clearly
theres no much play happening.
so do you guys think i should take it for a tune? or fiddle around
with wiring, fuel pressure, intake etcccc. and try to diagnose further?
also anybody knows a good performance tuner in orange county CA area?
thanks guys
idles great, but it overheats after driving after 20-30 mins,
it goes on "crawl" mode, put it on drive or reverse it wont even move!
new water pump, new radiator, im starting to think it needs a proper tune.
i used painless harness, painless said its plug and play but clearly
theres no much play happening.
so do you guys think i should take it for a tune? or fiddle around
with wiring, fuel pressure, intake etcccc. and try to diagnose further?
also anybody knows a good performance tuner in orange county CA area?
thanks guys
On The Tree
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Did you backfill the radiator hose on driver side first before just filling the radiator? If you didn't fill the block on driver side before filling radiator that could be your problem. Seen it several times cause this issue. I doubt your harness has anything to so with this unless your fans aren't coming on, if electric and based off of PCM trigger.
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backfill? not sure what you mean, i bleed it a couple of times to make sure theres no air pockets, fan turns on at 140deg, also took out the thermostat so the water can flow freely, the reason why i think it needs a tune is when i unplug the maf sensor the engine smooths out but when i plug it back in thr engine sounds horrible.
honestly im out of ideas, im about to just take this to a real mechanic lol
honestly im out of ideas, im about to just take this to a real mechanic lol
On The Tree
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By back filling I mean to remove the radiator hose that 'exits' the block and fill it up with coolant. Just remove the hose from radiator and use the hose that goes in the block as your funnel.
Several people skip this step and they have heating issues.
As far as running rough it sounds like another issue
Several people skip this step and they have heating issues.
As far as running rough it sounds like another issue
TECH Regular
Joined: Jun 2012
Posts: 414
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From: SV, AZ
Swaps have to be tuned to run properly. If you change anything ahead of the MAF sensor, or even clock it differently, it can(will) throw the calibration off. If your airmass is wrong your timing will be wrong. It sounds like your problem.
Last edited by eaglegoat; Jun 25, 2015 at 05:53 PM.
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Swaps don't have to be tuned to run correctly unless there's a cam in there or for the trans to be working properly if he's running a stock tune and a stock cam it should idle fine. The overheating also has nothing to do with a tune, if the ca idles better with the maf unplugged something is wrong. Check for vacuum leaks behind the maf, check the o2s as well as the maf itself.
As far as the overheating goes have you data logged it to be sure it is in fact overheating and not just the gauge going weird?
Also what do u mean you saw water drip when you took off the exhaust manifolds? Was is antifreeze? You should never have coolant coming from the exhaust manifolds unless it's in a boat....
As far as the overheating goes have you data logged it to be sure it is in fact overheating and not just the gauge going weird?
Also what do u mean you saw water drip when you took off the exhaust manifolds? Was is antifreeze? You should never have coolant coming from the exhaust manifolds unless it's in a boat....
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so when i drive it around for about 15 mins, the water temp rises to 200-210deg, then it would loose all power and it feels like it locks up, but when it cools down to 150 deg the power comes back and i can drive it again, which is again only a 15 min interval.
it locks up like when i put it on drive it wont even crawl at all, when you give it gas it literally wont move like im pulling a 20 ton trailer attached in the back. im puzzled i dont understand it thats why im calling it overheating
it locks up like when i put it on drive it wont even crawl at all, when you give it gas it literally wont move like im pulling a 20 ton trailer attached in the back. im puzzled i dont understand it thats why im calling it overheating
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Swaps don't have to be tuned to run correctly unless there's a cam in there or for the trans to be working properly if he's running a stock tune and a stock cam it should idle fine. The overheating also has nothing to do with a tune, if the ca idles better with the maf unplugged something is wrong. Check for vacuum leaks behind the maf, check the o2s as well as the maf itself.
As far as the overheating goes have you data logged it to be sure it is in fact overheating and not just the gauge going weird?
Also what do u mean you saw water drip when you took off the exhaust manifolds? Was is antifreeze? You should never have coolant coming from the exhaust manifolds unless it's in a boat....
As far as the overheating goes have you data logged it to be sure it is in fact overheating and not just the gauge going weird?
Also what do u mean you saw water drip when you took off the exhaust manifolds? Was is antifreeze? You should never have coolant coming from the exhaust manifolds unless it's in a boat....
Well 200 isn't even close to overheating that's actually what the cars run normally. So I think the cooling system is fine.230 is pushing it and 240 is overheating so with that said I don't think you have an over heating issue.
What combo is in the car? Like what trans, specs on the motor and what Pcm/harness are you using
What combo is in the car? Like what trans, specs on the motor and what Pcm/harness are you using
TECH Regular
Joined: Jun 2012
Posts: 414
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From: SV, AZ
Maybe our definitions of properly are different. For me if it's ideling like crap and my fuel trims are out of whack, then it's not right IMHO. If you swap something from a 5000lb truck into a 3000lb car then your timing needs to be redone. Will it run? Absolutely. Is it right? Not hardly.
On The Tree
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Condensation coming from exhaust isn't uncommon. Massive amounts are bad of course indicative or other problems. Again as stated by the other guy 200 isn't over heating. And fans coming on at 150 means your fan will never shut off and will become an annoyance (if fans on constantly bother you)
Maybe our definitions of properly are different. For me if it's ideling like crap and my fuel trims are out of whack, then it's not right IMHO. If you swap something from a 5000lb truck into a 3000lb car then your timing needs to be redone. Will it run? Absolutely. Is it right? Not hardly.
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well i tried to back fill the radiator to no avail, still the same, im telling you guys this **** is weird, im gonna get it towed to a performance tuner and get the ecu upto spec, trans is 4l80e and i used painless harness, engine is lm7 from 04 tahoe,
the 4l80e will not work with a stock 4l60e tune which is what came in 04 tahoes so that is most likely the limp mode problem you are getting. the pcm is tuned for a 4l60e and most likely is hitting limp mod because it isnt seeing one. however that and the temp is not related, 200 isnt overheating so the pcm will not do anything to put the car in limp mode because of that alone. what exactly arte you trying to accomplish by backfilling the radiator over and over?
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so i took the nova to a mechanic, theres a few issues to blame for the car going on limp mode...
the injectors spitting put 42lbs which is too high for the stock 28lbs, broken oring seal on the oil pump shaft, shreded spark plug wire causing the 5th cylinder to misfire, melted o2 sensor wire, broken knock sensor wire.
replaced everything above and now its running strong, incan get actual tire spins now from accceleration.
the injectors spitting put 42lbs which is too high for the stock 28lbs, broken oring seal on the oil pump shaft, shreded spark plug wire causing the 5th cylinder to misfire, melted o2 sensor wire, broken knock sensor wire.
replaced everything above and now its running strong, incan get actual tire spins now from accceleration.