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Troubleshooting help

X

XJKcali

NAXJA Forum User
Location
NorCal-San Lorenzo
Have an '88 I6 AT. Bought it from a guy who said that the temp gauge spiked, then overheated, and blew a head gasket (<-so says his mechanic). Took off the head, no sign of a blown head gasket, replaced it, buttoned it up. Go to start it, turns over, won't catch, temp gauge spikes all the way. Disconnect TSU wire but still spikes. Suggestions?
 
XJKcali said:
Have an '88 I6 AT. Bought it from a guy who said that the temp gauge spiked, then overheated, and blew a head gasket (<-so says his mechanic). Took off the head, no sign of a blown head gasket, replaced it, buttoned it up. Go to start it, turns over, won't catch, temp gauge spikes all the way. Disconnect TSU wire but still spikes. Suggestions?
Click to expand...
Start here..........http://www.naxja.org/forum/showthread.php?t=101119
 
Do you have the correct sender--rear of head, driver's side?

Cranks but won't start after replacing the head?

Battery fully charged, cleaned the cable ends, right? Did you remember to re-attach the one and only unibody ground at the rear of the head--braided strap from head to firewall? Did you check the ICM/ECU/o2 sensor grounds at the dipstick?

Try a couple shots of ether into the intake while you are cranking the engine.

Did you check for spark?
 
Checked all the grounds and connectors. Battery charged. Haven't tride either or checked for spark yet. What bothers me is the temp gauges going full deflection on start. The previous owner alluded to this prior to it overheating. I am just wondering if there is some fault that will cause it to overheat again. So I am kind of cautious on this.
 
No, dead cold and the gauge pegs just means that the sender/wiring/gauge is crapped out.

When you start the engine, a**uming the water pump works, the accessory belt is on and turning the pump, there is coolant (even if just water) circulating, it will take about 10 minutes of running to start getting warm.
 
Thanks, new to the XJ and after the previous owners explaination of the overheating I wasn't sure if there might be some other problem. I'll go ahead and try the other stuff.
 
I think I tracked it down to an injector issue. Have fuel presure and will turn over if I spray quick start, but won't run. Pulled a plug to smell for gas (flooded?) and it was dry as a bone.
 
The C101 is the bulkhead connector where the harness enters the passenger cabin from the engine bay--right there by the brake booster.
 
I look in that spot before and didn't see it. Is there a trick to popping off the lock? Also when I removed the wiper fluid bottle to get better access I found a flat brown plastic two conductor female plug that was not plugged into anything that I could find. Any ideas?
 
Last edited:
Thanks I found the screw. As far as the plug goes all the plugs on the washer bottle are accounted for. Unless the sensor broke off. Was it mounted to the top of the bottle? My bottle has two pumps and should have a sensor, and there is a spot on the top right that looks like it had something on it at one time.
 
Last edited:
So I plugged and unplugged the C101 harness conector. I also checked the CPS and it is OK. So what do I need to look for that controls the fuel injectors. It will run on quick start but thats it. I have spark, and I did a quick compression check on one cylinder and it was 150.
 
If you measure the voltage from ground to the green/orange wire (iirc) which goes to all the injectors (compare the wire colors on any two injectors, check the one that is the same color codes on both plugs), do you get ~13 volts? You should, that is power from the B+ latch / ASD relay.

If that works, check the bulkhead connector and trace back to the ECU. I only suggest checking the voltage on that wire first because it's way easier to check so might as well do it before the tough stuff. Always throw the cheapest parts first, and waste time on the fast stuff first!

EDIT: crap, now that I remember, might be wrong on that wire... RENIX I believe uses a common ground bus on the fuel injectors rather than a common power rail like OBD-I/II
 
Ful pump kicks in and there is fuel in the rail (haven't checked the presure). I rechecked the injectors with a noid light and still got nothing. I haven't played with any of ther relays yet. Thanks and keep the ideas coming. I am new to XJ's so this is a great learning experience.
 
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