Will a 1990 zr1 run in full power mode with a check engine ligt on

[GRAND SPORT #12]

I have heard a 1990 ZR1 will not run in full power mode if the check engine light is on. My question is if you happen to have one and the CEL is on is there any way to bypass this. The reason i ask is i have a L98 car and some parts that can set the CEL are not available any more.

 

[Hib Halverson]

What part can't you find?

 

[GRAND SPORT #12]

Hi Hib, on my l 98 car vacume switching valve for egr on a 91 getting tuff to find. The reason i ask i am getting ready to get a 1990 ZR1 and since it is getting older and some emissions parts are getting hard to come buy i was wondering if the CEL came on could you bypass so the engine would run in full power.

 

[Hib Halverson]

90-92 LT5s do not have EGR.

If the MIL is on and the code set disables the secondary port throttles, you could not bypass that.

If you are going to buy a used 90 and you're worried about parts support of emissions related items, before you buy, I'd make sure the engine and it's engine controls are in good condition.

Stock 90s had no valve stem seals on the exhaust valves and, because of that, they tend to use oil at a higher rate than do other LT5s. 91-95 LT5s have the exhaust seals.

Is the car you're considering have an MIL which is on?

 

[GRAND SPORT #12]

Hib the 90 does not have a mill code. My 91 at times sets one at times, pin pointed to egr vacume switching valve, and when i saw that the vacume switching valve to the egr was hard to find it got me thinking if something like that happened to the 90 and the part became unavailable what would be my options. I love my l 98 car, love my grand sport and was thinking of adding to the stable.

 

[xfirez51]

Hib the 90 does not have a mill code. My 91 at times sets one at times, pin pointed to egr vacume switching valve, and when i saw that the vacume switching valve to the egr was hard to find it got me thinking if something like that happened to the 90 and the part became unavailable what would be my options. I love my l 98 car, love my grand sport and was thinking of adding to the stable.

Does NC have OBD1 emissions testing? BTW, LT-5 parts are not difficult to find. Visit zr1.net

 

[Hib Halverson]

Hib the 90 does not have a mill code. My 91 at times sets one at times, pin pointed to egr vacume switching valve, and when i saw that the vacume switching valve to the egr was hard to find it got me thinking if something like that happened to the 90 and the part became unavailable what would be my options. I love my l 98 car, love my grand sport and was thinking of adding to the stable.

The question is moot because 1990 ZR1s do not have EGR. No EGR means the "vacuum switching valve" does not exist on the engine and, thus, it cannot fail. Same for 91 and 92 LT5s.

Starting in 1993, LT5s have EGR but it was the first application of a digitally-controlled EGR valve and, thus, the engines do not have vacuum switching valves.