Crappy Cold start problem, starts great when battery on last breath!
Thread Starter
Joined: Oct 2002
Posts: 3,509
Likes: 2
From: Raleigh, NC
Crappy Cold start problem, starts great when battery on last breath!
Ok guys,
I have a cold start problem which some of you may know about. I dont feel like resurecting myn old thread for people to have to read all through. I adjusted my TPS and thought that would fix the issue but it stills has a hard time starting when cold. I will turn it over and over and nothing right about till the battery is nearly dead.
Right when you think the starter will not give another turn, it catches all the sudden and fires right up. This is the third time I have noticed this in a row.
WTF?
I have a cold start problem which some of you may know about. I dont feel like resurecting myn old thread for people to have to read all through. I adjusted my TPS and thought that would fix the issue but it stills has a hard time starting when cold. I will turn it over and over and nothing right about till the battery is nearly dead.
Right when you think the starter will not give another turn, it catches all the sudden and fires right up. This is the third time I have noticed this in a row.
WTF?
HAILERS
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
You need to take a digital meter and backprobe the water thermo sensors wire AT the ECU and see if it's reading 2-3vdc with a cold engine and once fully hot.... 0.40 to 0.50 vdc.
You also need to backprobe pin 3B on the small plug of the ECU to see if it shows 8-12vdc when the key is HELD to START.
The last page on this thread https://www.rx7club.com/2nd-generation-specific-1986-1992-17/fuel-pressure-826006/page2/ starting with post #35 and on, is somewhat applicable to your case.
You also need to backprobe pin 3B on the small plug of the ECU to see if it shows 8-12vdc when the key is HELD to START.
The last page on this thread https://www.rx7club.com/2nd-generation-specific-1986-1992-17/fuel-pressure-826006/page2/ starting with post #35 and on, is somewhat applicable to your case.
Thread Starter
Joined: Oct 2002
Posts: 3,509
Likes: 2
From: Raleigh, NC
Ok after having read that thread I feel alot more confident I will find this problem here shortly.
It can be one of two things.
My thermosensor (which I have denied vehemently, which I will explain why in a sec)
And the start signal to the ECU.
Possible reason it may be the thermosensor:
When I had the motor in the vert I had a bad watermump. When I went to replace it I mistakenly tried to remove the housing rather than the pump itself. I yanked on it and realized that the sensor was still holding it in place, then further revealed how much a dumbass I am that I did not need to remove the housing, just the pump.
I plugged it all back in with the new pump and sure as ****, it wouldnt start right. It was running rough as hell. It took forever to start right, just like it does now but ran rough for the next few minutes until it got to operating temp.
I pulled the housing back off, and the sensor still looked plugged in, but I yanked the leads or connectors off the pins from the inside. I reconnected everything and siliconed the wire position on the plug so it wouldnt slip and it ran fine ever since.
The reason I have so vehemently denied it was the thermosensor was because now when I get the car started it runs fine the second after it catches, regardless of engine temp it seems. When it was the thermosensor before it ran like **** until it got to operating temp.
NOW:
The reason I think it may be the Start signal to the ECU.
When I removed the old blown motor from current car I fucked up the copper pipes that go to the heater core. I install other motor from vert just to find my feet soaked in coolant. I pulled the dash out and fixed the heater core.
In doing so I had to disconnect a bunch of harnesses and ****. I still have a few harnesses and plugs that are not connected and have no clue where they go. One is close to the ignition. I am thinking this might be a better way to attach this issue.
It can be one of two things.
My thermosensor (which I have denied vehemently, which I will explain why in a sec)
And the start signal to the ECU.
Possible reason it may be the thermosensor:
When I had the motor in the vert I had a bad watermump. When I went to replace it I mistakenly tried to remove the housing rather than the pump itself. I yanked on it and realized that the sensor was still holding it in place, then further revealed how much a dumbass I am that I did not need to remove the housing, just the pump.
I plugged it all back in with the new pump and sure as ****, it wouldnt start right. It was running rough as hell. It took forever to start right, just like it does now but ran rough for the next few minutes until it got to operating temp.
I pulled the housing back off, and the sensor still looked plugged in, but I yanked the leads or connectors off the pins from the inside. I reconnected everything and siliconed the wire position on the plug so it wouldnt slip and it ran fine ever since.
The reason I have so vehemently denied it was the thermosensor was because now when I get the car started it runs fine the second after it catches, regardless of engine temp it seems. When it was the thermosensor before it ran like **** until it got to operating temp.
NOW:
The reason I think it may be the Start signal to the ECU.
When I removed the old blown motor from current car I fucked up the copper pipes that go to the heater core. I install other motor from vert just to find my feet soaked in coolant. I pulled the dash out and fixed the heater core.
In doing so I had to disconnect a bunch of harnesses and ****. I still have a few harnesses and plugs that are not connected and have no clue where they go. One is close to the ignition. I am thinking this might be a better way to attach this issue.
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