Electrical issue after timing belt replacement

[ditchdoc77]

I bought this car with several issues.
1) bad #3 and #5 injectors. I took the plenum off and replaced all 6 injectors and replaced all vacuum lines I could reach. Started it up and the front of the timing cover was rattling really bad.
2) Replaced:
Timing belt, both pulleys (top one was bad), cam seals, front main, water pump, and hoses.
Put it all back together and fired it up. took for a test drive. When to the store and back (3 miles), the last 1/2 mile is rough dirt road. I was creeping along the rough dirt road and the engine suddenly stops on a bumpy section. I tried to crank it and wouldn't even try to start. temp was fine (I was watching it like a hawk) I towed it back home and still have not been able to start it. Will turn over but won't even try to start. I am assuming a wire came loose and I can't find it for anything.

I checked the crank angle sensor A with no continuity to ground. I have to have overlooked a ground somewhere for sure.
The top of engine has the double ground connected on drivers side top/back of plenum-ok.
Top of engine passenger side single ground connected. (However, I thought there was a second engine ground on passenger side top/back of plenum, just can't find anything within reach of it.)

When I first started it up after the timing belt replacement, I had to wiggle some wires at the crank angle sensor for it to fire up. The test drive had bad hesitation at any throttle over 10%.

ECU giving codes of: 11 and 13. temp and cas.

I have cleaned all connections and added dielectric grease to help with the connection. I am to the point of having to hire someone to help me find my missing ground. I have pulled the wiring diagram and cannot figure out where F11 is on the engine for the ground or where it comes out of the wiring harness.

Any thoughts or ideas on how to hunt this thing down?
This is my first Z and I plan on using it on a daily basis. 1990 Non-turbo 5-speed.

[t.mcginley.jr]

The only grounds on the plenum are the three you mentioned (2 on drivers side, one on passenger side). The main ground from the battery grounds on the firewall right by the battery and then on the trans bellhousing. There's also a small ground strap from the fuel rail to the lower intake manifold. I think there's also one ground on either frame rail. Besides that, the ECU itself grounds through the metal holder it's in so make sure that's tight.

Are you sure there aren't any breaks in the harness or loose pins on the CAS connector? You shouldn't have to wiggle anything so either you have a bad connector/wiring to the CAS, or the CAS itself is bad.

Also, a bad coolant temp sensor (code 13) will cause starting issues because it messes with the air/fuel ratio and the timing a little too IIRC.

[ditchdoc77]

Thanks for the info t.mcginley.jr. I'm out in the garage right now and looking for a solution.

I took out the radiator and R upper timing cover to inspect the CAS closer. Nothing looks out of place.

I have taken the CAS out and I don't see anything wrong with the shaft where they connect.

I think I am going to reinstall the CAS and manually turn the engine to see if I can hear the fuel injectors firing. I'm also going to look at this forum on how to test the CAS.

Let me know if you have any other ideas.

Ken

[t.mcginley.jr]

Here's how to test the CAS:

http://www.300zx.co.uk/cgi-bin/manual.c ... &total=190

If it's not the CAS itself, its probably the connector or the harness.

[ditchdoc77]

ok, I have an update.

I took the CAS off and tested it. I wasn't getting the voltage to 5v but did have change in voltage.
While I was there I took the coil pack and spark plug off the #1 cylinder, put them back together and set it on the plenum. As I rotated the CAS with ignition on, I heard the clicks rotating through each injector. However, no spark from the coil pack and plug I removed.

I started to do some more research and found an older post from you helping another member.

I remembered, after I finished the timing job and took it for the test drive to the store the engine shut down on the bumpy road when I was almost home (makes sense with loose and non-attached grounds on the plenum). after I towed it back, I found that I did not tighten the ground on the passenger side plenum and fail to even attach the two grounds on the drivers side.
In your post to the other member, you stated that if the ground is not connected, you could fry the PTU.

I saw evidence where the factory recalled PTU (black one) was wired in and the connections had a patina film on the blades. I cleaned them off and reattach, but still no spark. Could I have fried the PTU during my test drive? Does this also explain the hesitation at any throttle more than 10% just prior to complete shutdown?

Thanks again for your help, I've noticed that your quite the guru with tech help too.

Ken

[t.mcginley.jr]

It's very possible that you fried the PTU since it wasn't properly grounded while running. A bad PTU would definitely not let you start it, and the loose grounds would explain why you had all those other problems when it was running like you said.

Luckily getting a new style PTU is pretty easy, they came on a number of Nissan cars during the early to mid 90s. You can get a good used one on ebay for $24 shipped I believe.

And thanks for noticing haha I've actually only been in the Z world for almost a year now (got my 90 NA last June).

[ditchdoc77]

I just got the part in the mail and plugged it in. instantly the engine turned over and fired right up. All I have to do now is put some of these vacuum hoses back into place and reinstall the radiator. I'll be working on this when I get back home tonight. I'll let you know how it goes. Thanks again for your help.

Ken

[t.mcginley.jr]

Awesome man! Glad to hear it worked out and it's running now. It's always a good feeling when the car isn't running and you work on it and then it runs, feels great