Miss that is developing? (Help)

[TFENT]

Miss that is developing?

Ok so I had the Z in the garage for the last several months and I went to drive it last week and right out of the box the car would not start, cranked over but no start. Car is a 1990 w/ 32K all stock as far as I can tell. I let it sit for 20 minutes and went to start it and it cranked right up. But started to misfire.

I then drove it up to the gas station and dumped a van of Seafoam in it and 13 gallons of gas. It was running pretty rough then would smooth right out. Tried to drive it a bit then after 20 miles it stalled out at a light and cranked over but refused to start. Embarrassed I kept at it till it started and spit and sputtered. Died again. Then waited 30 more seconds and it started right up but with a heavy miss. Drove it 20 miles via freeway and no issues. In city driving at lights it is kicking and screaming, under part throttle even worst. Under heavy throttle runs pretty well. Popped a code 44 and 55. Now it is refusing to run hard under WOT so the problem whatever it is, is getting worst. Code 44 is Left O2 Sensor Lean, Code 55 is System Voltage.

I spoke to Jerry (Jerry?s Gaskets) and order O-Rings and gaskets in case I have to yank the Intake.

Its weird, the stalling makes me believe it could be a fuel pump because right after I start it, it runs pretty good. But the driving around and at an idle makes me think Fuel Injectors.

What are your thoughts??

Thanks in advance.

[rhipsher]

If they are the original injectors then its time to replace them. Its a well known fact the the ethinol in todays gas will eat them up and cause them to fail.

[XfireZ51]

Check fuel pressure. Start with filter then move towards back of car with fuel
pumps.

[TFENT]

Originally Posted by XfireZ51

Check fuel pressure. Start with filter then move towards back of car with fuel
pumps.

Ahhh, never changed the fuel filter...

[tomtom72]

Fuel filter & PSI test on the pumps like Dominic says.

The original owner of my car never changed the F/Filter, okay so he only did 7400 miles, but over 14 yrs. I r&r'ed it and the gas was orange that came out. I do it every yr now...maybe a bit of overkill

Remember that upon cold start both pumps run. Secondary pump shuts off after 140*(?) water temp is reached. On a warm/hot restart I think the secondary pump runs for a programed time limit, but I'm not 100% sure on that fact. KOEO pump test could be useful.

I know I swapped out my original pumps just this year just because they were 20 yrs old and I know they were testing at the lower end of the FSM acceptable PSI limits during the KOEO test.

When she acts up have you given a sniff to the exhaust? Does it smell rich or lean? I know the code says lean, but can you smell it? Did it make your eyes burn?

The time period description you give makes me want to say something electrical....you know as it heat soaks the issue gets worse. Generally that's what your symptoms seem to be saying. JMHO. Run down the pumps & filter, next I would look at checking for battery & alternator condition and then the ignition system condition, then the injector coils electrical condition.

Keep us in the loop and good luck!


Tom

[Mystic ZR-1]

Mine had all the same symptoms. 99.9% chance it's the fuel injectors. I had 5 of 16 out of spec. They're pretty reasonable $ @ fuelinjectorconnection.com or 770-888-1662 ask for John Banner. And get your gaskets from Jerry@ jerrysgaskets.com
Mystic ZR-1

[TFENT]

Originally Posted by tomtom72

When she acts up have you given a sniff to the exhaust? Does it smell rich or lean? I know the code says lean, but can you smell it? Did it make your eyes burn?



Tom

Tom:

No smell what so ever, either way. Doesn't smell like raw gas nor does it make your eyes burn.

I am going to change the fuel filter then check fuel pressure to give me a base line. If I am good there then I will just order fuel injectors from FI Connection and get 4 replacement coils. Swap those out and then if that doesn't solve the problem then I will replace the pumps.

I really wish someone had photos of them checking the fuel injectors on the ECM using Marc's instructions. So I can see exactly how to do it without messing up the pins.

[A26B]

Tom,
A little more information.

1. Always begin diagnostics with the lowest numerical DTC first. In this case, DTC 44. When the lowest code is resolved, the higher code will be too. Removal of stored codes is accomplished by disconnecting the battery for about a minute and is recommended.

2. There are 2 components to injectors, electrical & mechanical. A corroded or plugged injector can test just fine for coil resistance and still be the problem, so don't rely only on the ECM probe procedure unless it indicates defective.

3. ALWAYS keep the fuel tank full during long periods of inactivity. The pump assy can/will rust, plugging the strainers, fouling/ruining the pumps & clogging the filter.
Here's a photo of the one from my Ruby Zee. When it gets this bad, cleaning the tank is part of the fix.


4. For 90~92 models, injectors have been the predominate cause of misses without codes thrown, followed by bad ignition coils, then plug wires. Odds are, your's will be be fuel related considering the DTC 44.

Good luck with the repairs and keep us posted. Thanks for the advice during our telecon! I appreciate it

[TFENT]

Thank you Jerry!

I thoroughly enjoyed the conversation we had Friday, you are a wealth of of valuable information. I look forward to getting your gaskets and proceeding with the intake removal.

[A26B]

Tom,

Here's a photo diagram (made by a member to share his experience) from an old post I found.

Should help some. Also, FWIW, another member enlarged the connectors while probing for resistance checks on the injectors, creating a different 7 very elusive problem...intermittent connections. So, be careful while probing. & don't stick the probe into the connector.