Update on hesitation up to 3,000 RPM,then,clears itself..

[Vette73]

Car is fine upon start up and for the first ten mins or so......After that, hesitation bogging until 3,000 rpm....

So, I'm guessing primary fuel pump..50,000 miles I have and I'm guessing original pumps....

Bought my car around to my mechanic and make a long story short I have the fuel pumps out of the car.....Weird thing is today I'm driving back from there ( short distance)
,service engine light comes on but now car is running fine.....Get home and I parked it....Ten mins later I get into car and I figured I would just bring it back and get it scanned

Got a few blocks ( no service engine on light) and car started to do the original symptoms-- bogging until 3,000 rpm...

Just took it home parked it and removed the fuel pumps.....

Wonder why light came on but ran fine with the service engine light on....

Will keep everyone posted after I put the new fuel pumps in...

Peace...

[RussMcB]

When I had problems with my car not running well I attached a fuel pressure gauge to the fuel rail so I could see if the pressure was dropping at the same time the engine started running bad. That at least tells you if the problem is with fuel pressure.

Later I decided to install a permanent FP gauge in the car (but I never look at it now).

Good luck.

[tomcat]

Hello,

Have you swap out the fuel filter? Maybe an o2 sensor or EGR component maybe bad.
Manfred E....
91 ZR1 #906

[Vette73]

Originally Posted by tomcat

Hello,

Have you swap out the fuel filter? Maybe an o2 sensor or EGR component maybe bad.
Manfred E....
91 ZR1 #906

Swapped out fuel filter about 6,000 miles ago....Will see when I change pumps..

[G8nightman]

You should get the codes first it will tell you what it is and there’s a few ways to test the pumps


Sent from my iPhone using ZR-1 Net Registry

[Paul Workman]

I agree w/ others - TEST FIRST, replace after first determining (whatever) is actually bad. Never throw parts at a problem in hopes it goes away (which seems to be SOP for many (so-called) "mechanics".)

And, BTW, one of the best tools I ever bought for my first C4 was a scanner which could pull codes as well as give real time readings of 41(!) different parameters, AND featured the ability to record the dynamic sensor values when a problem was happening by pushing an "event" button. Saved me untold amounts of frustration - BELIEVE ME!

(NOTE: I've found that fuel related issues (for one) don't always throw a code right away, especially errant O2 readings don't immediately result in a code. (Marc Haibeck could tell ya for sure, but it seems the programming gives whatever is resulting in bad readings from the O2s a little time for the situation to truly establish itself as "real", before tossing a code: something to keep in mind.))

Getting ahead of the game, I attached pix of how to monitor fuel pressure under actual driving conditions, AND showing how and where to diagnose fuel pump current draw (and what the readings indicate).

[Vette73]

I guess I should have listened...I swapped out the fuel pumps and its still doing it...

I did the repair myself so I only paid for parts.....Funny thing is,the service engine soon light comes on and the car runs fine with the light on.....

I don't have any gauges so I will get it scanned at my mechanic this week..

[Demps]

http://www.zr1specialist.com/HAT%20W...0Info/aldl.htm

I would use the link above with a paperclip & see if the code is residual.

Ted

[Pete]

Hi John

If i had to guess, you have FIC injectors?

Pete

[Vette73]

Originally Posted by Pete

Hi John

If i had to guess, you have FIC injectors?

Pete

Hi Pete...
I believe accel..