badbird88

Ok, this isn't about my TA but about my wife's Isuzu Rodeo. First a little history on the problems we have had with it since day one such as hard to start or doesn't want to start, valves knocking/tapping constantly under any sort of acceleration and it wants to fall on it's face at times when you first crank it up and try to drive it.

Ok we filed the Lemon law since they keep saying it's a computer problem. Their fix (the service guy told me as a warning of what the Isuzu Rep was going to do ahead of time) was to put a colder spark plug in and see if that works. He said they came out with a new computer program but it was tried on other Rodeos and it didn't work. He said our Rodeo will be a first time try and we are the lab rats.

What does or will a colder spark plug normally do? Will it richen or lean the fuel mixture out, help the timing any or what? Thanks! If possible I need a reply before they call me and tell me what they did, even though I'm not suppose to know what they are going to try. Will this hurt performance or gas mileage?

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1988 TA 300+hp 350 w/ TBI and Holley TB unit, Holley projection intake,
WC T-5, 3.42 gears w/ Auburn posi. MSD 6A, edelbrock TES headers, dynomax 3" cat and cat-back system, ACCEL coil, polyurethane bushings all around, aluminum driveshaft, Mr. Gasket open air cleaner.

1993 S-10 w/ 4.3L V6 TBI, slightly bigger cam, Mild polish job and 3 angle valve job on heads, Edlebrock TES headers, Dynomax cat back, MSD 6A, ADS chip

2000 Kawasaki KX 125

badbird88

anyone have any advice on what a colder spark plug will do to any motor...f-body or not?

RB83L69

Colder plugs simply run with their tips at a lower operating temp, by the ceramic having a shorter path to the casting to conduct heat away from the tip. Often the kind of pinging you are describing (which has nothing whatsoever to do with the valves BTW) can be caused by the plug glowing red-hot and igniting the fuel mixture too early.

"Fall on its face when you try to crank it up and drive it" is caused by not enough fuel when the motor is cold. Hard starting, especially when cold, is often caused by the exact same thing. Try replacing the coolant temp sensor; or if you have or can get a scanner, see what the ECM thinks the coolant temp is. If it is getting wrong info about the engine temp, it may not know that the motor is cold, and to enrich the fuel mixture to compenste; or that it's hot, and to back the timing off to keep from knocking.

Colder spark plugs, within reason (liek one or 2 heat ranges) will not significantly affect either performance or mileage.

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"So many Mustangs, so little time..."

JP84Z430HP

What year and enigine? Some of the older ones had the GM 2.8/3.1 v6 in them, and would be pretty easy for us GM guys to troubleshoot.

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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

ASE Certified Master Tech

Starting to look like the Kicker poster child!

badbird88

It's the new 3.2 liter 200 hp engine. They changed to some wierd name spark plug and went down to a colder plug as they said they were going to do. They also cleaned the upper intake with some sort of cleaner but it was probably the cleaner you use in the cylinders to clean the carbon out. The SUV only has 7500 miles on it. The original plugs were champions....hmmm.

The motor had a different tone to it, a little noiser actually but no valve knocking. I thought maybe it had actually worked since the zone rep and 2 other service guys rode in it and didn't have it do it with them. But I got on a road with some slight hills, just enough to put a very small load on the motor and the valves went to tapping all the way up. It's like it doesn't have enough octane or the timing is to far advanced. The motor came out in 99 and it has some sort of ION sensing ignition that is supposably the prob but I don't care anymore b/c that was the final time they had to fix it. The hard starting problem didn't do it with them but it is random anyways and will probably do it with us tomorrow. Either way it appears that it is going to be Lemoned or replaced more than likely since they don't like to lemon law them. If it was my TA I would try a few things and not worry too much but on a brand new vehicle I'm not going to screw with anything and let them replace it. The thing that really bothers me is the starting problem. What if my wife gets in it to start it and it won't start and she is stuck somewhere...that would tick me off especially for her safety if it's at night.


[This message has been edited by badbird88 (edited January 10, 2001).]