So I took my car to get smog today for transfer and two things failed. Timing was not set to 10*...that was an easy fix. But the EGR solenoid was failing to open the valve. The shop tested the valve and it worked fine. They also checked the plug for power and there was power, but when they grounded the EGR solenoid it will not open. They suspect the pintle inside the solenoid is stuck and suggested replacing. I get a random SES light, I pulled the code and it was 32.

Car is a 91' 5.7 TPI. I went to order the solenoid and can't find a GM part #. Does anybody know of a reliable aftermarket EGR Solenoid to use in place of the GM part number?

 

Base timing is 6dbtc with the est disconnected.

https://www.thirdgen.org/forums/tpi/...-solenoid.html

 

I had it at 6* but the placard/sticker under the bottom of the hood on a 1991 says 10*, so that is where they want to see it. Thanks for the info.

 

Hope you confirmed the base timing in your tune is 10* as well!

 

What sticker is saying a base timing of 10? Should 6.

 

https://www.thirdgen.org/forums/tpi/...-solenoid.html

 

The one that's located under the hood for emissions testing. I set it 10* and it passed smog today, the EGR solenoid pintle must have freed up. Here is the pic of the sticker for reference.

 

Not sure I’m that brave to set timing in drive .

 

Me neither I just set it while idling warm with the EST disconnected with my timing light to 10* BTDC as I don't know what the SMOG techs are looking for or checking. But the first time around they claimed it wasn't at 10* like on the placard/sticker and wrote that up as a failure. So I set it to 10* like the sticker says so if they are using a timing light they can see for themselves. I'm not sure if it will hurt anything when I had my 87' and 90' 5.7 I always bumped the base timing up a couple of *. I listened for any detonation under load pulling hill in OD part throttle and then at WOT...no KR or pinging that I could hear.

If DR does mean Drive, I suppose they should be looking for 10* BTDC while running on the rollers at 2500 rpms. But the test procedures on the placard/sticker (left side) don't state to do that. They simply state to disconnect EST and set timing.

 

That decal looks to me like a it is from a V6, it is NOT from a V8... the LH0 3.1 liter is supposed to run with 10° BTDC and a spark plug gap of 0.045". V8 TPI needs 6° BTDC and spark plug gap of 0.035"
Did you or the PO replace the hood with a V6 Firebird hood?

EDIT: I was right, it is indeed from a 91 3.1 V6. Google the part number of your decal 10145439 (lower right corner) and you will find this: http://www.gmpartswiki.com/getpage?pageid=129920

 

That means initial SA is 6* in your tune! Now your SA is off by +4* all over.

 

That is an interesting find. My only other Thirdgens were an IROC which had indentations in the hood for the louvers, and a 90' (Formula 350) and 91' (V6) the hoods were different on these cars as the Formula had the raised portion.

For this 91' I just picked up it has the blister hood bulges on top. I guess these could have been added to a V6 hood?? Here is a pic.


The vin is a TPI or has an 8 for 5.7l. Maybe the original hood was damaged or the wrong sticker got put on it?

 

Yes, you can buy just the blisters and install them on the base flat hood. https://www.hawksmotorsports.com/lou...blisters-pair/

 

Yea that decal or hood has been swapped, or maybe someone at the factory pulled a lazy move!

Either way, I'd definitely correct timing to be 6BTDC and replace that decal for future smog endeavors.

 

I just love that the stupid California emission testers completely screwed this up.

 

Yes but because of it I learned something new about my car. Funny thing is I told the guy 6* for a 350 when he came out to the lobby and then he took me into the shop to show me the sticker...so I thought it must have got changed.

This hood looks original as the entire car is very clean with only 50K original miles on it. Either way I'm taking that sticker off or I will write in the timing and correct plug gap.

Is there any benefit to leaving the timing bumped a few degrees? I didn't notice anything negative running the car the past few days with the base timing at 10*. I plan on re-setting the base timing tomorrow to 6* unless some compelling reason...like better performance of leaving it advanced???

Thanks everybody for chiming in to help sort this out. This is one of the best forums I've been on.

 

You will need to replace the sticker with the correct one, they won't take hand-written notes.

Yes, there is negatives to leaving the timing bumped. You're going to have spark knock and it'll retard your timing, negatively affecting performance.

 

You are going to be +4* all the way including WOT.

 

Thanks I am just going to pull the sticker off and they can check the book for timing if it ever requires smog again. Also I live in one of the few counties in California that doesn't require bi-annual smog. The only smog required is for title transfer to a non linear family member. Meaning if I wanted to give the car to my mom, child, grandparent then it doesn't require smog. However I wouldn't be able to give it to my brother without having a smog check. I even gave a car to my step son and DMV didn't ask for smog. My step son son was standing right next to me the same day he got his driver's license when I gave him the Firebird Formula 350 and transferred the title.

I'm definitely going to do some minor mods to this car, such as exhaust and intake with tune. But I'm not going to LS swap mod this car after all of the compliments I've been getting. I own quite a few vehicles and so far everywhere I have driven the last couple of weeks people have stopped and told me nice or beautiful car. Younger 20-25 year old men..it has been surprising to both me and my wife. The only other car that gets equal thumbs up is my fully restored 66' Mustang and it is loud with a 400hp motor. I drive my C7Z06 and Tesla and they get occasional looks, but never a thumbs up or verbal acknowledgement. Not that that is of some extreme importance, it is just nice to see ThirdGens getting some re-surging love in this day and age.

But I have to do something to add a few ponies to the L98. TPIS quoted me $7800 for a 4 bolt main 350cid with Miniram and a supplied tune (450+ hp). That might be a consideration someday if I go to replace the motor. I'm not doing an LS swap, I do like the idea of it especially having the stock blower from my Z06 sitting on the shelf. I thought about buying a new LT1 and adding the blower to it, but that means a new tranny and wiring...its just not worth it to me when there are 350-450hp SBC available that will bolt right in.

I think a ThirdGen with 300-400hp is a good range for daily driving and is enough to get past the little ricers, and be respectable around the newer muscle performance cars. I'm never going to track this car, I use my C7Z for track and none of them will out accelerate my Tesla to 60 mph. The Tesla is really a soulless ugly car in comparison. But 0-60 in 2.9 secs is pretty fun in commute traffic.

Thanks for the advice I'm going to put the timing back this morning when I change the oil.