Earendil

Yes, I have the "full power key".


I could not see much of a difference between on and off even before these problems started. The vacuum pump works fine. It has no major leaks.. when the ignition is ON it will start for 1 sec every 30 seconds or so.. But I doubt it is the secondary valve system.. tha car has problems in idle also and it would stall mostly in low end rpm... not the other way around.










..

Earendil

I can now confirm it is not the fuel.


I have taped the manometer on the windshield during drive and during driving and all the stalling - the pressure holds good 42 psi..


I guess this rules out the fuel?


What's next? New sprak plugs, cables and coils?

Tom400CFI

"Shut completely off at 100? It's hard to fully understand the symptoms, but that sounds more electrical (ignition) than fuel, however, your comments about varying fuel pressure, and pressure rising after shut down cause me concern (pressure shouldn't rise after shut down). You definitely DO need to get a longer hose on your gauge, so you can observe it while driving, under load and while the symptom is occurring.

Catalytic converters (that are clogged) basically cause problems at larger throttle openings. If a converter is clogged, the more air the engine wants to flow, the more of a symptom the converter will create. The symptoms will be; Lack of power, LOTS of intake/induction noise. The symptom is typically very, very consistent; every time you open the throttle, you get a "bog" and lots of intake sound. Typically, the engine will run smoothly thought -at low throttle openings it would run normally and smoothly, and during the symptom, it would run smoothly too...just w/no power and lots of intake sound. It would not likely shut the motor off. So based on they symptoms I've seen you describe, it doesn't seem like clogged cat(s).

EDIT: Copy on the fuel pressure. Good work. When the symptom occurs does the engine run erratically? Or smoothly (but lacking power)?

Earendil

Smoothly.. I would say no.. it hesitates to get going from low RPM.. At higher rpm it runs.. well not well, but it goes fairly smoothly all the way up to 7k rpm.
It is mostly when I try to drive normally.. i.e. take it up to 2.5 - 3k rpm, shift up.. and then as it tries to take off from 1.5 rmp it stalls like it completely clogged.. regardless if I press hard or just lightly.. speed drops and sometimes it would suddenly take off as it should.. but sometimes I have to shift back down, and revv it much higher, so I can shift up again..

I now it is hard to understand the symptoms from my writings and limited English vocabulary.. I have ordered new spark plugs tomorrow and I will try to make a video so you can see and hear for yourselves if there's no improvement after the change.. just to rule them out.
I have just checked the cables in the dark and they seem fine.. sprayed some water even to see if smth happens..

Mishawaka

Sounds like your fuel pressure is good. Have you checked for a good blue spark at the plugs? I'm not a great mechanic but I would start there. Maybe use a timing light with an induction pickup to make sure every plug is getting spark? Just my two cents.

Maybe a video with with audio would help?

cv67

May have multiple problems going on if youre getting the err msg
Bad injectors, as the car gets warmer will miss even more
If they are original plan on replacing them with some Rcs.
You really need to post this stuff up on the zr1.net forum that will be your best source of info to eliminate some headache and guessing

Tom400CFI

I'd check (ohm) the injectors, test the Throttle position sensor, and observe the tach signal when the missing is occurring.

Earendil

Alright next up will be the injectors.. but I'll probably have to order these from the US.


Today I am changing the plugs.. what is the normal gap? 0.9 - 1.2 mm?

Tom400CFI

That sounds about right.

Earendil

What is this for?


https://www.dropbox.com/s/8lx3la6ac1...24.30.jpg?dl=0


Looks wobbly , but the contacts inside seem fine. Throttle position?


Where is the MAF? Thought to try with MAF disconnected..


Spark plugs did not change a thing..

mtwoolford

well, it is low mileage, but it's still a 93; changing the plugs didn't help, but I'd change the pug wires also, at that age the insulation and the conductor (assuming OEM) will have hardened up and produced a zillion micro cracks which drive resistant way up, and may even allow voltage to escape. Also, change the fuel filter; age hardens the element on those too and restricts fuel flow, especially at high engine loads.

before you can diagnose some issue, you need to have a good baseline to start; i.e. a through tune up, and then go from there.

Good luck; it sounds like you have an awesome ride.

whalepirot

I believe so. Your English is okay, friend.

I read on Marc Haibeck's web site about problems with the secondary throttle system. As suggested, the ZR1 boys may chime in with more remedies.

http://www.zr1specialist.com/HAT%20W...es%20index.htm

Checking the injectors as Tom suggested is a great idea.

Earendil

Managed to pull out err.51 from the ECM. No idea what to do with it?
Deleted some other codes as well.. 02 sensor, poor fuel mixture.. they did not reappeared after a short drive, but the "51" error is permanent.








Some kind of memory chip error? ideas?

whalepirot

I loaned a CF member my manual so cannot look up the code; also have no experience with '93s.