Last Ride

Hey all--
Well, I got a rude awakening today. Cruising around town with about a quarter of a tank of fuel left when all of a sudden, the car sputters, backfires, and dies. I couldn't move it anywhere! I got it to the side of the road, still reading a 1/4 tank. All of a sudden, the digital guage goes to one bar! I got my wife to bring me some gas, and it started right up. I made it to the gas station for a fill up. Is this a common problem? How can I correct the guage? It looks like the list of stuff I have to do to "the car I could just drive" is growing! Thanks for the help!

Jeffvette

Sounds like the float arm has a cach in it.

Bans25

that must be something new with that Z..., when I test drove that car, it was on empty and the owner had me stop to fuel up. While I was talking to him he mentioned it was a brand new sending unit and pumps that he paid big $$ for (then I broke the news to him about the Suburban fuel pumps, and his jaw dropped)

Last Ride

I just had a thought on this. Would a DRM chip cause an sort of "mis-reading"? This chip I have is pretty radical (for the 368). I was going to swap it out for the stock chip for around-town cruising, but I haven't got to it yet. Any thoughts?

Bryan

DDSLT5

The chip won't affect the fuel guage. I wouldn't recommend putting the stock chip in - it was calibrated for 350 cids - at wot, you'll likely lean out the engine since you now have 368 cids, and more porting.

fhturner

Hey Last Ride--

Did you ever get this problem sorted out? I believe I'm having a similar problem on my recently purchased '90 ZR-1. I don't know if it was happening before I got it, because it had a full tank of gas (for storage) when I test drove it and bought it. But, the first tankfull (driving back to B'ham from Dallas) decreased normally on the gauge as I drove. After my first fill up, though, I noticed that after driving 100 miles, the gauge had dropped maybe one bar. It does seem to drop, but I think that, like you, when my gauge shows 1/4 - 1/2 tank, I'm out of gas. BTW, you didn't say: How much gas did it take when you filled it back up?

L8r,
Fred

White 68

On my 91 the gas reading has always been alittle wierd...I keep track of how much gas I put in and how many miles I drive just to make sure. My problem is when the car get to about a 1/4 tank it says I,m on reserve and shows about 40 miles til empty ..Put as the reading gets down to say 20 or less miles it resets back up to 40 miles til empty and will continue this routine until it hits Low fuel ....
Anyone else have this happen ?

Last Ride

Haven't got it sorted out yet, but the car went to the shop today. Hopefully, we will get it sorted out and I will have something to report. It took at or around 19 gallons when I finally filled it up.

Bryan

FU

Ran into this problem on my 90. Pull the Fuel sending unit and use a ohm meter to see if it is sending the correct values to the CCM. IE: vary from the full position and gradually lower the float. The ohm's should go lower. Do this procedure slow. If the ohm meter get's stuck at any output contact me (IM) and I'll tell you how to fix it. It is so easy you would be supprised.

HTH

fhturner

Sorry to be dense, but I don't (yet) have my service manuals for the Z. Where do I pull the fuel sending unit, and how to I manually lower the float? This sounds involved-- does it require taking a lot of things apart?

Thanks for the help and info, Frank!
Fred

JaySS

I have pretty much convinced myself that the fuel gauge will not decrement properly if the mileage calculator is left in the "Range" mode. Put nearly 300 miles on the car, and it only dropped 1 notch on the bargraph. Maintain Inst. or Avg. mileage on the display, and it works properly.

Anyone else notice this?

- J

Last Ride

When mine left me stranded, it was on "Average MPG". I usually don't use the "Range" meter, but I did this just to see how far I actually had. Well, 87 miles turned into about 87 feet!

Bryan

fhturner

Mine is usually on Average MPG as well. I sometimes switch into the Range mode just to see if it is part of this "conspiracy" as well. Sure enough, it will show some absurdly high range (400+ miles remaining when I've already driven 100-200 miles)...

FU

Remove fuel door.
Remove fuel cap.
Pull rubber off the fuel neck (Gently)
You will then see the unit, a screwdriver and a nut driver and it comes out easy.

AlHale

I am having the same problem! Somewhere around 3/8-1/2 tank it goes to empty quickly! Have you tried the Techtron fuel additive solution? I am curious. I am going to try it and see if it works.

Thanks,
Al
94 385 LPE

ZRWON

Thanks Frank...think mine has same problem

phrogs

Well my guage has always been a little wierd

Whenever I get to reserve and fill it up it usually takes about 9 gallons to fill her up.

I purposly ran her to fumes once with spare gas with me, after the guage got to reserve and the last 2 bars were gone I got another 70 miles out of it. I dont remember how much gas I had to put in her after that but it was like 15 or 16 after the 2 gallons from my gas tank.


Also when I do fill it up the guage doesnt read all the way to the top as I know it should I think my float arm is bent and is just not reading right on mine, Yours may be the same way, also on the ZR1 net theres a part in the know problems that the bladder in the tank can fall in on itself and cause a lower feul load??

I doubt thats your problem especially if you got 19 gallons into it!

DDSLT5

Car got the right owner then, eh?

I'm sorry - it's been a typical monday, and now I'm taking it out on the hard working fella protecting my useless azz in the world's biggest beach. Come home soon buddy! :flag

jhong321

I had the same problem. It all started one day when I filled the tank all the way to full. After that the fuel gauge read full even after I put 200 miles on it. At this point I pulled the pumps and adjusted the floats (they where sticking to one of the fuel pump clamps. It seem to work but now when I get to about 1/2 tanks on the gauge there will only be about 3 gallons of gas left. I am still trying to find the right fix. But i think this is very common