Colin 86&87 IROC-Z

alright, this is really starting to confuse me... here's the deal. My Dad says that in California they reformulate the gas here in the winter for better economy or something. Either way, he says that the gas is different than gas you buy in the summer. I set the timing on my '86 after changing the EGR valve and restabbing my distrib. Set it to 6 BTDC. Omg, that thing was pinging so damn bad. So I backed it off, and even at 4 ATDC it's still pinging. I've been having this same problem with my '87 for the last 3 months as well! At 0 BTDC it still pings bad enough under WOT that at 3200rpm or so it will ping bad enough for the ESC to kick in. This is getting frustrating! My '87 has a fresh rebuild in it, and I have to retard the timing so much that at idle my oil pressure drops REAL LOW because my engine is retarded so much... I can run supreme, but I'd really like to figure out what the heck is going on here.. I did disconnect the EST when I set my timing and both engines were warm when I set it so I know that they weren't in high idle... ideas?

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'86 IROC-Z 305/auto with no cat, performance chip, shift kit, and 4.11s
'87 IROC-Z factory loaded with every option, 84,000 miles

Webmaster: www.IROC-Z.org

irocz

I've heard the same thing about Calif. gas. You might just have to add octane boost for a few months.

good luck,


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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP cam, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax/Flowmaster catback
Coming Soon - Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - STOCK (for now)
SOLD ->91 Z28, 5.7, 3.23, Ported Plenum, Accel runners & lower intake, Accel distributor module, !dual cats, POS Edelbrock catback, K&N'S, ram air, tb airfoil, !tb coolant

Andy89RS

The only additive I know of to Cali's gas is MBTE (MTBE?) which is in there year round. It's not like we get enough of a winter to need reformulated gas for those frigid temps of low 60's... Especially if you've been having those problems for the past 3 months I would suspect it's not the gas, they definitely wouldn't have a winter formula gas in Cali in the middle of 100+ temps. If you always use the same station maybe you should try another one just to be certain they aren't selling you bad gas...

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"Racing is life. Everything else is just waiting." - Steve McQueen - LeMans

305 TBI, T-5. 15.4@92 mph
Member Southern California Third Gen F-Bodies

AOL IM: Andy89RS

fb305svs

well, just to add a little to this- gas for 100 degree weather is formulated to not evaporate as easily vs gas for 60* weather. there is a difference. but it shouldnt make a difference in the octane rating. anyhow, double check everything over to make sure the timing is right. sounds like you have already done that, so move on to the fuel system- maybe you are running a little lean. have you replaced the o2 sensor lately? all things to check...

Steve

Colin 86&87 IROC-Z

both of my cars have new O2 sensors, MAT sensors, knock, coolant temp... when I take off a part, I change anything around it that's easy to get at, even if it's not toasted yet, just to make sure that I wont have to worry about it later... I've bee using ARCO gas, maybe I'll run Texaco for awhile... i did find out that my '86 doesn't have a performance chip, which would make both of my IROCs stock except for the 4.11s in my '86... the weird thing is, I didn't have this problem last year with my '87.. but that was last year.. i'll try running another company's gas and if that doesn't work i'll run a few tanks of 92 octane and see if that clears it up...

how much would a decent scanner be? what's a good model? from what I can tell they are like 300 bucks? thanks for the help guys

Matt_Ky

FYI,
In KY we have a summer blend and a winter blend of gas, however, both blends are RFG.
I would try buying gas at a different station
and run 92/93 octane. You could be getting water in the gas. I just heard this past week of a guy locally that pumped 30 gallons of water into his tank. Made it 2 blocks. Service station is picking up the repair bill.
Later