: Mid-grade fuel?



lovepuppy
05-17-04, 01:57 PM
Hi,

A friend borrowed my 94 Eldo (northstar) and, I later found out, filled it up with mid-grade (89 octane) fuel. I always use 92, like the manual says it requires. Is there any chance that using lower quality gas for just a relatively short time like this could result in any problems or damage to the engine?

OlManRivah
05-17-04, 02:51 PM
No problem. That's one reason why I don't lend my vehicles out. I get the vehicle I really like, and keep it maintained well. Short time use of lower octane will not damage the engine. It probably didn't perform as well, and may have pinged, but, it'll be OK.

Geno Castellano
05-17-04, 11:18 PM
Hi,

A friend borrowed my 94 Eldo (northstar) and, I later found out, filled it up with mid-grade (89 octane) fuel. I always use 92, like the manual says it requires. Is there any chance that using lower quality gas for just a relatively short time like this could result in any problems or damage to the engine?

The engine will run fine on regular or mid-grade. You might notice some slight loss of power or fuel economy under certain conditions but the engine is fine and wouldn't be damaged even on a continual diet of the lower octane fuel. The knock control system on the Northstar is very effective and will prevent any spark knock or pinging before it's even audible.

J.A.O.
05-18-04, 09:47 PM
since you brought it up, I've notoced that under heavy acceleration (using 93 fuel) the engine sometimes will ping and if i let off and then try again it's gone. It's my understanding that the system has retarded the timing to counteract the pinging. is this true?

Geno Castellano
05-19-04, 02:29 PM
since you brought it up, I've notoced that under heavy acceleration (using 93 fuel) the engine sometimes will ping and if i let off and then try again it's gone. It's my understanding that the system has retarded the timing to counteract the pinging. is this true?

No, the knock sensor should react faster than that I'd say. Possibly the EGR valve is starting to stick slightly and lagging in the EGR supply, Unless you are going WOT then the EGR may be causing the knock.

There may be times where the knock control may be a bit slow to correct the detonation if you just changed fuels or just filled up at a station and got some lower octane fuel. On the first accelleration there might be a slight knock until the system learns the octane rating of the new fuel load. But that's remembered by the PCM so it should only happen once or twice after a fill up.

Yaemish
05-21-04, 08:06 PM
I run 93 in my Eldo all the time and 89 in the Deville all the time. I have switched up to 89 in the Eldo a few times and noticed no difference. THe Deville continues to run just as well as the Eldo with no pinging.

jgr7
05-21-04, 11:57 PM
with 91 running in the $2.38 -$2.48 range here I went back to 87 for $2.22 runs fine.

Jeff