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Runs great cold stumbles warm?


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I see from searching there is a lot out there regarding Loyales that run poorly cold and well when warm. Car in question is 90 Loyale Wagon 5spd 2wd.( SPFI )

 

Mine is the opposite. Go out first thing in the AM, runs perfect for 2-3 minutes. Cold acceleration smooth as silk and peppy. Once the gauge needle shows any temp at all, hesitation and stumble on acceleration, estimate 20% power loss from cold condition, although car does run and accelerate, but feels labored compared to easy free accel feel cold. Feels like the car is unshackled when cold and breathing through a straw at times when hot. Highway cruise is fine when hot. When accelerating from stop you notice small "spots" in the rpm range where car seems held back.

 

New o2 sensor.

 

TPS goes smoothly through range of voltage when tested. However, resistance stays at 2k ohms or so instead of dropping to 700-1000 as per Haynes.

 

Idle speed hot +-700 rpm

Idle speed cold +- 2000 rpm

 

Hottest inside temp gauge reads is 1/4 from bottom.

 

Parts on order from Chaplins include fuel filter, t-stat, dist cap, rotor, coolant temp sensor. Soon to arrive and hopefully address issue!

 

 

Ideas?

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Ideas?

 

TPS goes smoothly through range of voltage when tested. However, resistance stays at 2k ohms or so instead of dropping to

700-100 as per Haynes.

 

I don't understand how a TPS symptoms would exhibit when warm and not cold. I can understand this with CTS or AFM, O2 sensor, etc. TPS I would think would either be faulty or not independent of engine temp...

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TPS goes smoothly through range of voltage when tested. However, resistance stays at 2k ohms or so instead of dropping to

700-100 as per Haynes.

 

I don't understand how a TPS symptoms would exhibit when warm and not cold. I can understand this with CTS or AFM, O2 sensor, etc. TPS I would think would either be faulty or not independent of engine temp...

 

The over rich mixture it provides is inconsequental until warm.

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I don't understand how a TPS symptoms would exhibit when warm and not cold. I can understand this with CTS or AFM, O2 sensor, etc. TPS I would think would either be faulty or not independent of engine temp...

 

The over rich mixture it provides is inconsequental until warm.

 

I thought, perhaps erroneously, that most issues with TPS, AFM, would result in lean condition.

 

Leaning out sort of fits my symptoms. Feels like the car is not getting enough fuel. My tailpipe is not sooty nor do I notice smoke either. For some reason I get the feeling that too rich is not the issue, but again, who am I to say. I might make a run down to pick n pull tomorrow and see if I can get a TPS. I hate parts like this used though since they are typically off a car at least as beat up and miled out as mine, and no way to know if THEY are bad. I think there is a 92 Auto and an 87 Auto AWd down there...

 

thanks

 

matt

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I hate parts like this used though since they are typically off a car at least as beat up and miled out as mine, and no way to know if THEY are bad. I think there is a 92 Auto and an 87 Auto AWd down there...

 

thanks

 

matt

 

No worries-take your ohmmeter.It will show bad ones 100% of the time.

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check the engine temp sensor. its the one on the therostat housing with the green pigtail

 

see if the car runs different when unplugged, or try cleaning the contacts

 

pocket item at the junkyard, just bring the 17m wrench

 

may as well get the MAF sensor too, just unscrew it fro the housing. be careful not to break off the filamments(if you put it in your pocket)

 

beware that loyale MAF fits differently than pre loyale spfi's with the shape of the hole on the housing, ,but work the sae essentially

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check the engine temp sensor. its the one on the therostat housing with the green pigtail

 

see if the car runs different when unplugged, or try cleaning the contacts

 

 

The other day while troubleshooting this, I think I did unplug the temp sensor and the idle sped up considerably. I plugged it back in, and idle returned to normal. ( warm )

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suppose when you unplug the sensor and the car thinks its cold, wouldit run better?and if so there is your proble with the tmp sensor

 

try unplugging the maf while the car runs. if the car stalls the maf should be good, but if it keeps running the maf is bad

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suppose when you unplug the sensor and the car thinks its cold, wouldit run better?and if so there is your proble with the tmp sensor

 

try unplugging the maf while the car runs. if the car stalls the maf should be good, but if it keeps running the maf is bad

 

Will do with the MAF. I got a MAF out of a junkyard 92 the other day, and switched them out, no difference. Either they are both bad or both good. I will try driving with the coolant temp sender unplugged and the engine hot and see what gives.

 

thanks for your replies.

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