Cold start problems
03-26-2011, 12:38 PM
#1
Instructor
Thread Starter
Cold start problems
My car is an 88 and I have replaced the fuel injectors from John on the forum here.The fuel filter has been changed and all pressures checked and ok.The car also has new relays.I just checked for spark and it has a good spark so I am wondering about the cold start injector.Can I secvice this or replace it?Any ideas would be appreciated.
03-26-2011, 09:59 PM
#2
Race Director
I"m not sure about repairing a cold start. Jon may be able to help. A check of the price of the switch will give you sticker shock. The 89 did away with the cold start injector. Enriches the fuel/air mixture for start ups. You could either have your chip upgraded to 89 level or buy one from one of our chip people. I have an 85 I upgraded to your ECM, the chip burned is based on an 89 chip. Cold start injector is non operational. Works very well.
03-27-2011, 03:14 AM
#3
Le Mans Master
Describe "cold start problems".
You mean extended cranking time on cold starts?
'88 was the last year a 9th cold start injector was used. '89 and up no longer had it for cold start enrichment.
The voltage source for the cold start circuit is the 5 AMP "Crank Fuse" which feeds the Purple starter solenoid wire. The fact that the starter spins proves this fuse is good and the wiring up to the solenoid is good. This fuse is located in auxiliary fuse panel hidden behind the center of the dash in back of the information display.
There is a cold start injector thermo-time switch threaded into the front of the intake below the TB. Green circle in pic below. This switch is wired between the starter solenoid and the cold start injector and acts as a coolant temp controlled on/off ground switch. The Purple starter solenoid wire I mentioned earlier has a splice leading directly to the time switch which is also Purple on both the switch and injector connectors. The other terminal of the time switch and injector connector is Tan and is the ground wire. Both wires and the same wires and colors on both the switch and injector connectors.
This thermo-time switch only allows the cold start injector to be energized during cold starts when coolant is below 35 degrees. Depending on the coolant temp in the block, this switch is either open or closed to ground (Tan Wire). Again, two wires, Tan and Purple. One is hot with the key in "crank" position which is a directly splice from the Purple starter solenoid wire. The other is the ground side of the cold start injector (Tan). If the coolant is below 35 degrees, the thermo-switch will complete ground on the injector side (Tan) and allow it to spray fuel when cranking cold. If hot it will remain open and the Tan ground side of the injector will not t have contact and will not spray fuel. This is what controls the cold start injector. It's basically a temp controlled on/off ground switch wired to the cold start injector.
Get a noid light test kit from Harbor Freight or rent it from Autozone and disconnect the cold start injector connector on the driver side of the intake. Since the release clip is facing towards the intake manifold use some type of hook or tool to depress it while you pull it off with your other hand. I use two long flat tip screwdrivers. One to depress the clip and the other to pop the connector off at the same time. Once the injector connector is off install the correct noid light to the connector.
Autozone Part# 27161
Harbor Freight Item # 97959
http://www.harborfreight.com/11-piec...set-97959.html
Make sure the car is completely cold and crank the key. The noid light should stay lit (not flash) for the same amount of time the starter is spinning (because remember that the voltage wire is a direct splice coming from the switched purple voltage wire of the starter solenoid so it's the same switched voltage feed the starter solenoid is seeing). If it lights up this just told you everything up to the injector connector is working. Ohm test the injector across it's two terminals. Infinite resistance would indicated an open coil.
If the injector is good then remove the air duct and shoot some starter fluid into the throttle body before your next cold start and see if that makes it start right up on the first shot. If not then the cold circuit isn't your problem.
If the noid light does not light up first disconnect the cold start switch and test for switched voltage at the connector Purple wire. This is not going to be easy becuase of all that AIR clutter at the front of the engine is in the way. I use two long flat tip screwdrivers for this. Because it's a feed splice off the Purple starter solenoid wire you should be seeing battery voltage on this wire at the same time the starter is spinning. There should also be continuity between both Tan terminals on the thermo-time switch and injector connectors as well as between both Purple wires. I would not be surpirsed if the wires colors have faded and no longer look Purple and Tan just like they where on mine.
If voltage is not present at the thermo-time switch connector Purple wire but starter spins check the wiring between switch connector and Purple starter solenoid wire.
Cold start time switch is in Green Circle.
If you need a new termo-time switch it's Autozne part# EDS4
(Ignore their false description that calls it an "EGR" switch)
http://www.autozone.com/autozone/par...8613_173005_0_
You mean extended cranking time on cold starts?
'88 was the last year a 9th cold start injector was used. '89 and up no longer had it for cold start enrichment.
The voltage source for the cold start circuit is the 5 AMP "Crank Fuse" which feeds the Purple starter solenoid wire. The fact that the starter spins proves this fuse is good and the wiring up to the solenoid is good. This fuse is located in auxiliary fuse panel hidden behind the center of the dash in back of the information display.
There is a cold start injector thermo-time switch threaded into the front of the intake below the TB. Green circle in pic below. This switch is wired between the starter solenoid and the cold start injector and acts as a coolant temp controlled on/off ground switch. The Purple starter solenoid wire I mentioned earlier has a splice leading directly to the time switch which is also Purple on both the switch and injector connectors. The other terminal of the time switch and injector connector is Tan and is the ground wire. Both wires and the same wires and colors on both the switch and injector connectors.
This thermo-time switch only allows the cold start injector to be energized during cold starts when coolant is below 35 degrees. Depending on the coolant temp in the block, this switch is either open or closed to ground (Tan Wire). Again, two wires, Tan and Purple. One is hot with the key in "crank" position which is a directly splice from the Purple starter solenoid wire. The other is the ground side of the cold start injector (Tan). If the coolant is below 35 degrees, the thermo-switch will complete ground on the injector side (Tan) and allow it to spray fuel when cranking cold. If hot it will remain open and the Tan ground side of the injector will not t have contact and will not spray fuel. This is what controls the cold start injector. It's basically a temp controlled on/off ground switch wired to the cold start injector.
Get a noid light test kit from Harbor Freight or rent it from Autozone and disconnect the cold start injector connector on the driver side of the intake. Since the release clip is facing towards the intake manifold use some type of hook or tool to depress it while you pull it off with your other hand. I use two long flat tip screwdrivers. One to depress the clip and the other to pop the connector off at the same time. Once the injector connector is off install the correct noid light to the connector.
Autozone Part# 27161
Harbor Freight Item # 97959
http://www.harborfreight.com/11-piec...set-97959.html
Make sure the car is completely cold and crank the key. The noid light should stay lit (not flash) for the same amount of time the starter is spinning (because remember that the voltage wire is a direct splice coming from the switched purple voltage wire of the starter solenoid so it's the same switched voltage feed the starter solenoid is seeing). If it lights up this just told you everything up to the injector connector is working. Ohm test the injector across it's two terminals. Infinite resistance would indicated an open coil.
If the injector is good then remove the air duct and shoot some starter fluid into the throttle body before your next cold start and see if that makes it start right up on the first shot. If not then the cold circuit isn't your problem.
If the noid light does not light up first disconnect the cold start switch and test for switched voltage at the connector Purple wire. This is not going to be easy becuase of all that AIR clutter at the front of the engine is in the way. I use two long flat tip screwdrivers for this. Because it's a feed splice off the Purple starter solenoid wire you should be seeing battery voltage on this wire at the same time the starter is spinning. There should also be continuity between both Tan terminals on the thermo-time switch and injector connectors as well as between both Purple wires. I would not be surpirsed if the wires colors have faded and no longer look Purple and Tan just like they where on mine.
If voltage is not present at the thermo-time switch connector Purple wire but starter spins check the wiring between switch connector and Purple starter solenoid wire.
Cold start time switch is in Green Circle.
If you need a new termo-time switch it's Autozne part# EDS4
(Ignore their false description that calls it an "EGR" switch)
http://www.autozone.com/autozone/par...8613_173005_0_
Last edited by 86PACER; 03-27-2011 at 03:28 AM.
03-27-2011, 11:38 AM
#4
Instructor
Thread Starter
So this morning I get some gas and a squirt bottle all ready to go and I think I will try it without any gas and the car starts up no problem.I ta ke it for a drive and go to the car wash(leave it running)come back home and shut the car off and leave it for a few seconds and it won't start back up.I press the throttle to the floor and it fires a bit but didn't stay running.I am wondering if the cold start switch has stuck and now the car has flooded.Is it common for these switches to be intermittant?Thanks for all the replies BTW.
03-27-2011, 02:23 PM
#5
Le Mans Master
That is possible too. The thermo-switches can fail open or closed. I've had that happen to me too with my other car. Thermo-switch got stuck stuck closed and was firing the cold start injector even when hot. Everytime I would stop at a gas station it would refuse to restart.
Try disconnecting the cold start injector. You can also use the same noid light to see if the injector is being energized by the thermo-time switch when hot when it not supposed to be.
Try disconnecting the cold start injector. You can also use the same noid light to see if the injector is being energized by the thermo-time switch when hot when it not supposed to be.
03-28-2011, 04:59 AM
#7
Instructor
Thread Starter
03-28-2011, 09:31 AM
#8
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The car has always started good for me. I do have the long cranking problem that some have had, but when cold, I will crank for 1-2 seconds, turn key off and reprime pump and then the car has always started right up and ran great. Fuel pressure is good and regulator checks out. It's never been an issue so I've never looked into the long cranking as the wife's subaru starts better this way cold as well.
04-12-2011, 12:55 PM
#9
Instructor
Thread Starter
I replaced the cold start switch and started the car and let it warm up,then shut it off and then it wouldn't start.I am really at my wits end with this thing,I am afraid to drive it anywhere in case I cant get home.On another note,what is the sensor right beside the cold start switch on the front of the intake?I may have damaged it,does anyone know what this is and what it does?
04-12-2011, 02:25 PM
#10
Le Mans Master
Temperature sensor to the ECM. Did you test things and use a noid light or did you just throw parts at it?
When it's hot and doesn's start again connect a timing light to any spark plug wire and see if the light flashes while cranking. This wil rule out an intermittent no spark when hot.
When it's hot and doesn's start again connect a timing light to any spark plug wire and see if the light flashes while cranking. This wil rule out an intermittent no spark when hot.
04-14-2011, 12:11 PM
#11
Instructor
Thread Starter
Temperature sensor to the ECM. Did you test things and use a noid light or did you just throw parts at it?
When it's hot and doesn's start again connect a timing light to any spark plug wire and see if the light flashes while cranking. This wil rule out an intermittent no spark when hot.
When it's hot and doesn's start again connect a timing light to any spark plug wire and see if the light flashes while cranking. This wil rule out an intermittent no spark when hot.
05-02-2011, 12:46 PM
#12
Instructor
Thread Starter
This problem turned out to be a vats key problem.Cleaned the key and starts perfect.........ordered a vats bypass.The car was burning fuel left behind in the intake I guess but the injectors were not alowing it to stay running because of the vats sytem fail.Car is running good and starting well,thanks for the replies.
06-05-2011, 12:52 PM
#13
This problem turned out to be a vats key problem.Cleaned the key and starts perfect.........ordered a vats bypass.The car was burning fuel left behind in the intake I guess but the injectors were not alowing it to stay running because of the vats sytem fail.Car is running good and starting well,thanks for the replies.
