L98 - Hard start when “warm”

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Apr 26, 2005 | 10:06 AM

viii

Thread Starter

Racer

Joined: Jun 2001

Posts: 377

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From: Chicago IL

L98 - Hard start when “warm”

Its an 85 with 52k and has always been hard to start when warm – when cold, no problem when hot, no probem, when warm--- long cranks. I searched the posts on this topic and came up with two solutions. Fuel injectors and the fuel filter, so I changed them both (pink top injectors). Still have the hard start when warm. I read somewhere that the mat sensor could be sending bad info due to a “heat soak” condition. I know there is a mat relocation kit available apparently for this purpose, any thoughts or other ideas? Thanks.

Apr 26, 2005 | 10:14 AM

65Z01

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From: SE NY

Cruise-In II Veteran

I think that the tuner guys have said that the MAT isn't used on the L98 engines except for the EGR function.

Try disconnecting your cold start injector. The temp sensor/timer under the TB in the front of the intake base may be faulty.

Apr 26, 2005 | 10:33 AM

Total Recall

Instructor

Joined: Aug 2003

Posts: 139

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From: South Cave, Brough East Yorkshire

Hi.

Not sure why it worked like this - but on my car exactly the same problem was caused by low fuel pressure which was caused by a leaking fuel dampener in the tank.

Why it started fine cold and fine when hot straight after shut down I don`t know - but anything in between it was a nigtmare to get going - and it smelt awful of fuel.

It won`t neccessarily b the problem on your car but it could be. My fuel pressure used to drop straight off the second after shut down - or after the fuel pump shut off b4 starting.

Good luck!

Dom

Apr 26, 2005 | 10:41 AM

8388

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St. Jude Donor '14

Just because you recently changed out the injectors, doesn't necessarily mean they are not leaking. I'd take a fuel pressure reading, or you can pull a few sparks right after warm up, if they are wet with fuel, there's your answer.

Apr 26, 2005 | 11:16 AM

vader86

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From: Athens AL

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Check the fuel pressure reading after you shut the car off. It should hold steady.

Apr 26, 2005 | 01:51 PM

viii

Thread Starter

Racer

Joined: Jun 2001

Posts: 377

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From: Chicago IL

thanks for some good suggestions. I am going to pull the plugs and check for more leaky injectors. I'll get a guage and check fuel pressure. Does anyone know if it is possible to test the Intake Air Temp sensor with a voltmeter? I'd like to rule it out if possible.

Apr 26, 2005 | 02:07 PM

Morley

Drifting

Joined: Mar 2005

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From: GA

Quote:

Originally Posted by viii

Does anyone know if it is possible to test the Intake Air Temp sensor with a voltmeter? I'd like to rule it out if possible.

Yes, there is a chart around somewhere that lists ohm readings vs temp. This is actually for the coolant temp sensor but it is the same p/n as the IAT.

Apr 26, 2005 | 02:55 PM

grapidssteve

Instructor

Joined: Nov 2003

Posts: 126

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From: Belmont MI

Check the pick up coil on the distributor. I had exactly the same condition on my '85. There is a test for this in the Haines manual using a voltmeter.

I replaced the distributor on mine with a rebuilt one. The pick up coil failed and it took 4-6 weeks to figure it out, going through many of the same recommendations that you've gotten. The guy at Autozone was finally able to figure it out. Score one for Autozone.

It is not a difficult fix, and it cost about $16.

Hope this helps.