Drivability Issues
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Full Member
Joined: Dec 2009
Posts: 74
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From: Hickory, North Carolina
Drivability Issues
I just recently bought an 87 rx7 non-turbo for my stepson and i have been trying to get it sorted out before turning him loose in it. The problem is, I cant get it sorted out.
1) I can start it in the morning and it will flucuate its idle from 950 to 1500 and eventually rest at 750. I was able to get the idle adjusted to 750 but the cold start up and down scares me.
2) I can be driving along and all of a sudden i start to loose power. Not all the time but once every three days or so. When you step on the accelerator it starts to stumble badly. I can lightly put my foot on it and it will only rev to2000rpms or 2500 at the most before it starts hesitating. So i had to drive home at 23mph this evening. Now tomorrow when i start it up it may drive fine and may idle fine.
3) some days on cold start it wont idle at all. it will jump up and down between 500rpm and 350 until it stalls. It will restart without problem but i will have to hold my foot on the gas. But as soon as i can get it to rev to 6500 rpm it will run just fine and idle at 750 beautifully. But there is no telling what it will do after i am 25 miles away from the house. i went to the autostore this evening and it ran fine. Once i got back in the car to come home it wouldnt idle.
So my only option left was to lay my hand on the hood and start praying. Does anyone have any ideas? i would appreciate it. Because i think the car is possessed.
by the way its an automatic.
1) I can start it in the morning and it will flucuate its idle from 950 to 1500 and eventually rest at 750. I was able to get the idle adjusted to 750 but the cold start up and down scares me.
2) I can be driving along and all of a sudden i start to loose power. Not all the time but once every three days or so. When you step on the accelerator it starts to stumble badly. I can lightly put my foot on it and it will only rev to2000rpms or 2500 at the most before it starts hesitating. So i had to drive home at 23mph this evening. Now tomorrow when i start it up it may drive fine and may idle fine.
3) some days on cold start it wont idle at all. it will jump up and down between 500rpm and 350 until it stalls. It will restart without problem but i will have to hold my foot on the gas. But as soon as i can get it to rev to 6500 rpm it will run just fine and idle at 750 beautifully. But there is no telling what it will do after i am 25 miles away from the house. i went to the autostore this evening and it ran fine. Once i got back in the car to come home it wouldnt idle.
So my only option left was to lay my hand on the hood and start praying. Does anyone have any ideas? i would appreciate it. Because i think the car is possessed.
by the way its an automatic.
Last edited by fastboy2468; Dec 28, 2009 at 11:03 PM. Reason: add more...
Joined: Aug 2001
Posts: 6,096
Likes: 9
From: So Cal where the OC/LA/SB counties meet
See below:
I just recently bought an 87 rx7 non-turbo for my stepson and i have been trying to get it sorted out before turning him loose in it. The problem is, I cant get it sorted out.
1) I can start it in the morning and it will flucuate its idle from 950 to 1500 and eventually rest at 750. I was able to get the idle adjusted to 750 but the cold start up and down scares me.
- If you're talking about the 1500 idle at first start up, slowly dropping down to 750 as it warns, that's normal. Design to heat up the cats.
2) I can be driving along and all of a sudden i start to loose power. Not all the time but once every three days or so. When you step on the accelerator it starts to stumble badly. I can lightly put my foot on it and it will only rev to2000rpms or 2500 at the most before it starts hesitating. So i had to drive home at 23mph this evening. Now tomorrow when i start it up it may drive fine and may idle fine.
- Sounds like you have a bum TPS causing the engine to go into limp mode. Only cure is to replace it.
3) some days on cold start it wont idle at all. it will jump up and down between 500rpm and 350 until it stalls. It will restart without problem but i will have to hold my foot on the gas. But as soon as i can get it to rev to 6500 rpm it will run just fine and idle at 750 beautifully. But there is no telling what it will do after i am 25 miles away from the house. i went to the autostore this evening and it ran fine. Once i got back in the car to come home it wouldnt idle.
- Laying hands on the hood has value this time of year to warm your hands. Otherwise I think you need a human cure rather than look for the Divine. 
Replace the TPS and have it adjusted by someone that has experience doing it. Sounds like it's time for you to ask the forum for mechanic recommendations for your area.
So my only option left was to lay my hand on the hood and start praying. Does anyone have any ideas? i would appreciate it. Because i think the car is possessed.
by the way its an automatic.
1) I can start it in the morning and it will flucuate its idle from 950 to 1500 and eventually rest at 750. I was able to get the idle adjusted to 750 but the cold start up and down scares me.
- If you're talking about the 1500 idle at first start up, slowly dropping down to 750 as it warns, that's normal. Design to heat up the cats.2) I can be driving along and all of a sudden i start to loose power. Not all the time but once every three days or so. When you step on the accelerator it starts to stumble badly. I can lightly put my foot on it and it will only rev to2000rpms or 2500 at the most before it starts hesitating. So i had to drive home at 23mph this evening. Now tomorrow when i start it up it may drive fine and may idle fine.
- Sounds like you have a bum TPS causing the engine to go into limp mode. Only cure is to replace it.3) some days on cold start it wont idle at all. it will jump up and down between 500rpm and 350 until it stalls. It will restart without problem but i will have to hold my foot on the gas. But as soon as i can get it to rev to 6500 rpm it will run just fine and idle at 750 beautifully. But there is no telling what it will do after i am 25 miles away from the house. i went to the autostore this evening and it ran fine. Once i got back in the car to come home it wouldnt idle.
- Laying hands on the hood has value this time of year to warm your hands. Otherwise I think you need a human cure rather than look for the Divine. Replace the TPS and have it adjusted by someone that has experience doing it. Sounds like it's time for you to ask the forum for mechanic recommendations for your area.So my only option left was to lay my hand on the hood and start praying. Does anyone have any ideas? i would appreciate it. Because i think the car is possessed.
by the way its an automatic.
Thread Starter
Full Member
Joined: Dec 2009
Posts: 74
Likes: 0
From: Hickory, North Carolina
Thread Starter
Full Member
Joined: Dec 2009
Posts: 74
Likes: 0
From: Hickory, North Carolina
When i got it home last night it would hardly run but today it started right up and idled at about 1250 and slowly came down to 750 as it warmed. So i let it sit there and idle and it idled for about 30 mins as smooth as a kitten and suddenly it fell to 500 and started purging up and down between 500 and 250 rpm. I tried to give it gas but i could only do so slowly and it would only go up to about 2500 and start purging between 2500 and 2000rpm.
I'll adjust the tps today and if thats not it i will look at the thermosensor. I really appreciate you guys giving me some feedback. This rotary engine is a totally different monster from the conventional V's.
Last edited by fastboy2468; Dec 29, 2009 at 09:56 AM.
Sounds like throttle body adjustment issues. If you are able to come around the Statesville area, I can take a look at it for you. Don't let the rotary upset you. They can be finicky at times.
MECP Certified Installer
Joined: Feb 2009
Posts: 3,176
Likes: 3
From: Mesquite, TX-DFW
Thanks clokker I'll try that as well today.
When i got it home last night it would hardly run but today it started right up and idled at about 1250 and slowly came down to 750 as it warmed. So i let it sit there and idle and it idled for about 30 mins as smooth as a kitten and suddenly it fell to 500 and started purging up and down between 500 and 250 rpm. I tried to give it gas but i could only do so slowly and it would only go up to about 2500 and start purging between 2500 and 2000rpm.
I'll adjust the tps today and if thats not it i will look at the thermosensor. I really appreciate you guys giving me some feedback. This rotary engine is a totally different monster from the conventional V's.
When i got it home last night it would hardly run but today it started right up and idled at about 1250 and slowly came down to 750 as it warmed. So i let it sit there and idle and it idled for about 30 mins as smooth as a kitten and suddenly it fell to 500 and started purging up and down between 500 and 250 rpm. I tried to give it gas but i could only do so slowly and it would only go up to about 2500 and start purging between 2500 and 2000rpm.
I'll adjust the tps today and if thats not it i will look at the thermosensor. I really appreciate you guys giving me some feedback. This rotary engine is a totally different monster from the conventional V's.
So, my advice, test it at several temperatures if possible. Just because it is right at 70* doesn't mean it is going to be correct at 40*.
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the water thermosensor will have the biggest effect on the actual starting process--how long it takes for the engine to "catch" as it's cranking over.
The thermosensor is part of a choke-like function in the ECU. With a bad thermosensor, it's like trying to start a cold carb'd motor without the choke. During cranking, the primary injectors fire at the same time (batch fired) and leading and trailing ignition timing are fixed at 5 degrees BTDC. The water temperature signal and the engine speed signal are the only things that determine the cranking fuel amount.
The thermosensor is part of a choke-like function in the ECU. With a bad thermosensor, it's like trying to start a cold carb'd motor without the choke. During cranking, the primary injectors fire at the same time (batch fired) and leading and trailing ignition timing are fixed at 5 degrees BTDC. The water temperature signal and the engine speed signal are the only things that determine the cranking fuel amount.
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