Another engine temp related thread & engine hesitation
Another engine temp related thread & engine hesitation So after an opti & water pump swap some of you's on here have been helping me with (yay go me 
) the only issue is the engine temp.
The problem; the gauge will go from the 180 mark to 210 which i think is normal, to the 3rd peg right before the redline on the temp gauge. At this point i thought maybe i got a bad tstat out of the box (also new) so was going to replace that but someone suggested it wasn't the cause. I also thought air in the system but I have bled it and the heat stays hot now after it warms up. Everything is hooked up correct as far as the hoses go, i don't see how people swap them backwards unless they're completely replacing the system. I also did the TB bypass while i had it all apart but doubt that's related. Forgot the mention the temp will only climb when not moving, if i'm moving or the AC is on it will over cool if anything, according to the gauge going back to 180.
The block was never completely empty of coolant, once the opti & balancer where back on so went the water pump & hoses. From there I added coolant from the water pump. After that the tstat and the rest went back on and i filled from the rap with the top bleeder screw open. I don't know what to do besides RE BLEED, which is getting old, and change out the tstat.
As far as the hesitation once warm and in gear the car will go to 500-600 rpms and almost die out at every stop. The ICM and COIL are new and even had the old ones on there to rule out parts, since I was hoping it was just an icm issue and not the opti when it wouldn't start up. So now i'm thinking possibly the 02 sensor? What else might it be?
) the only issue is the engine temp.The problem; the gauge will go from the 180 mark to 210 which i think is normal, to the 3rd peg right before the redline on the temp gauge. At this point i thought maybe i got a bad tstat out of the box (also new) so was going to replace that but someone suggested it wasn't the cause. I also thought air in the system but I have bled it and the heat stays hot now after it warms up. Everything is hooked up correct as far as the hoses go, i don't see how people swap them backwards unless they're completely replacing the system. I also did the TB bypass while i had it all apart but doubt that's related. Forgot the mention the temp will only climb when not moving, if i'm moving or the AC is on it will over cool if anything, according to the gauge going back to 180.
The block was never completely empty of coolant, once the opti & balancer where back on so went the water pump & hoses. From there I added coolant from the water pump. After that the tstat and the rest went back on and i filled from the rap with the top bleeder screw open. I don't know what to do besides RE BLEED, which is getting old, and change out the tstat.
As far as the hesitation once warm and in gear the car will go to 500-600 rpms and almost die out at every stop. The ICM and COIL are new and even had the old ones on there to rule out parts, since I was hoping it was just an icm issue and not the opti when it wouldn't start up. So now i'm thinking possibly the 02 sensor? What else might it be?
Keep in mind that w/o a tune to change your fans' start temps (for low speed and also high speed), the fans do not begin (at low speed) until about 212 F; so if you are 100% sure that you do not have air in the system, and you used a stock temp t-stat (210 F vs. the SLP 160 degree F unit), then running at about 210 is "normal".
If, however, your fans never kick in when stationary with the A/C OFF, then you have an electrical issue (i.e. - relay or fuse or fusable link).
Can you clarify your problem?
At idle, with the A/C on HIGH / Recirc do both fans run at High speed? If they do, then the issue might be one of the coolant temp sensors; I say sensors (plural) as my 96 has two - one for the dash, one for the PCM. Your OBD I 94 may only have one temp sensor - IDK...
If, however, your fans never kick in when stationary with the A/C OFF, then you have an electrical issue (i.e. - relay or fuse or fusable link).
Can you clarify your problem?
At idle, with the A/C on HIGH / Recirc do both fans run at High speed? If they do, then the issue might be one of the coolant temp sensors; I say sensors (plural) as my 96 has two - one for the dash, one for the PCM. Your OBD I 94 may only have one temp sensor - IDK...
I guess my problem / question is with the stock OEM tstat and the previous owner saying it ran stock temp around 210 it should be staying there correct? I can post a picture later but the temp gauge will go to the third peg near the red before I'll turn it off, again only while not moving with no AC. AC on and it'll drop. That's why I'm thinking either the tstat was sticking oror my fans aren't kicking on by themselves.
If you broke the temp sensor in the water pump & the parts house gave you the wrong one itll read off on the gauge & if you didnt break em Take both out & use a wire wheel on the bench grinder to clean all the build up off em I wouldve super flushed it prior to installing a new water pump & made sure all that was flushed out Use green coolant **** that red stuff
I'm going to replace the tstat & bleed the system again tomorrow. I feel like it shouldn't over cool / not reach operating temp if the tstat was working properly. I'll update after that.
No one gave an idea to the stuttering & low idle problem. The car did it before the opti crapped out said the last owner and it has a new icm with thermal grease, coil & opti and still will hesitate at idle. Oxygen sensor maybe? Or dirty maf?
No one gave an idea to the stuttering & low idle problem. The car did it before the opti crapped out said the last owner and it has a new icm with thermal grease, coil & opti and still will hesitate at idle. Oxygen sensor maybe? Or dirty maf?
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Verdad Gallardo Can someone confirm that air in the system would NOT cause over cooling, if anything it'd be over heating correct? The car doesn't reach 180 even according to the gauge when driving so of course my heat would be luke warm at best, trying to rule out air or a clogged core, the heat as been dead hot after i let it sit so i still think my tstat is to blame, It will be in a frying pan once i get a replacement 
i'll keep the progress updated. Still does it, i don't get it. Drained coolant, replaced tstat, refilled and bled this time on ramps too. Maybe after another bleeding session or two. I want to replace the sensor that sends to the gauge that's in the block or head right? IS IT THE SAME SENSOR THAT'S IN THE WATER PUMP? I cannot find two sensors for this car so that's what i'm assuming ? 
I'm hoping my hesitation issues is the exhaust leak coming from the manifold where the air fittings use to be, I have yet to get a solid fix on that. I burnt the crap out of my fingers because for some reason I thought touching it after it was running for a few minutes was smart, felt the leak before my fingers got scorched. All little stuff at this point knock on wood.
Last minute thought, what's the fuse(s) i need to check for the fans? They are coming on with the AC but I don't think while idling without it.
I'm hoping my hesitation issues is the exhaust leak coming from the manifold where the air fittings use to be, I have yet to get a solid fix on that. I burnt the crap out of my fingers because for some reason I thought touching it after it was running for a few minutes was smart, felt the leak before my fingers got scorched. All little stuff at this point knock on wood.
Last minute thought, what's the fuse(s) i need to check for the fans? They are coming on with the AC but I don't think while idling without it.
The sensor in the head is only for dash gauge,the sensor on the pump is for PCM/ECM fuel & timing calibration if the one on the pump ***** the bed/has bad connection/or disconnected..it will cause drivability issues as will an exhaust leak,dirty MAF or bad o2's over heating at an idle and not at speed is usually a sign the fans arent turning on
Scan for DTC codes and fix the fan issue.
Christ it seems every thread is regarding this same bullshit
Scan for DTC codes and fix the fan issue.
Christ it seems every thread is regarding this same bullshit
I had/am still having the same exact problems bro, but mine will all be fixed w/ my header install and tune. Check and see when your fans are coming on! I ruled that out because I knew the fans came on, but figured out later they weren't coming on until the car got all the way up to that 3/4 mark where is stays running at unless I'm on the freeway.
I think the fans turning on late is attributed to either a faulty coolant temp sensor or the oil sensor, or both. My car runs mint but get's 3/4 hot unless going fast w/ air rushing in, and once it's up that hot I get the low RPM miss/die feeling just like you, which I'm pretty sure is the engine pulling timing to protect itself because it's so hot.
Check your fan turn on time and holler back
PS - in my case I think my oil sensor is faulty, occasionally my "low oil" light will come on on the dash when everything is fine so that's why I think it's related to the fan turn on time, as well as the coolant sensor.
I think the fans turning on late is attributed to either a faulty coolant temp sensor or the oil sensor, or both. My car runs mint but get's 3/4 hot unless going fast w/ air rushing in, and once it's up that hot I get the low RPM miss/die feeling just like you, which I'm pretty sure is the engine pulling timing to protect itself because it's so hot.
Check your fan turn on time and holler back
PS - in my case I think my oil sensor is faulty, occasionally my "low oil" light will come on on the dash when everything is fine so that's why I think it's related to the fan turn on time, as well as the coolant sensor.
Teching In
Joined: Sep 2011
Posts: 1
Likes: 0
From: Waco and Dallas Texas
If you have actually verified your fans are turning on too late, then you can fix it a number of ways.
1 - They should be turning on sooner regardless.. factory programming is set to have them come on at like 210 or 220 IIRC. I was told a bad coolant temp sensor and/or oil sensor can cause it, but not 100% sure on that one. I know on my car my oil sensor is faulty and sets off the light on the dash even though there is nothing wrong, and I am having the same problem with my fans so it could be related.
2 - Just wire in a manual fan switch, or buy the kit from one of the vendors on the site. They are around 60 bucks last I looked.
3 - Get a tune, a tune is nothing but good for your car anyway. If you don't want to spend the money on a full tune for performance, you can pay just to have the small changes made like the fan turn on temp, speedo recalibration, ect. and it will cost alot less. LT1PCMTUNING (solomon) does it as well as many others.
1 - They should be turning on sooner regardless.. factory programming is set to have them come on at like 210 or 220 IIRC. I was told a bad coolant temp sensor and/or oil sensor can cause it, but not 100% sure on that one. I know on my car my oil sensor is faulty and sets off the light on the dash even though there is nothing wrong, and I am having the same problem with my fans so it could be related.
2 - Just wire in a manual fan switch, or buy the kit from one of the vendors on the site. They are around 60 bucks last I looked.
3 - Get a tune, a tune is nothing but good for your car anyway. If you don't want to spend the money on a full tune for performance, you can pay just to have the small changes made like the fan turn on temp, speedo recalibration, ect. and it will cost alot less. LT1PCMTUNING (solomon) does it as well as many others.
The low oil light most certainly will not keep the fans from coming on, mine is unplugged completely because I have a deeper pan on my new motor and no provisions for the dummy sensor .. And I have the ever so annoying light lit and fans work as commanded... Just been to lazy to jumper the pigtail to turn the light off.. Now on some cars the low oil situation will cut fuel ... Not fans