No oil pressure / No idle
03-10-10, 03:18 AM
#1
Junior Member
Thread Starter
Join Date: Mar 2010
Location: California
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
No oil pressure / No idle
So, the '88 FC I just bought is starting me out with a couple brain teasers. The guy I bought it from said it overheated so he parked it. When I tried to start it, it turned over fine, but didn't want to fire up. When it did, it died immediately. The next time I got it to fire, I was able to keep it running with the gas pedal, but then noticed that it was showing no oil pressure, so I let it die.
From what I've read, no oil pressure is oft times a sending unit failure. I'll be replacing it just to make sure that it isn't the problem.
I've also seen that the idle problem could be due to leaking vacuum lines, however, everything I've seen on that is related to TII, and this one is NA. Could this still be the issue?
The worst-case-scenario center in my brain is worried that these problems are related -- that possibly something has gone wrong oil-wise (failed pump?) and the heat/not wanting to idle is due to lack of lubrication. Let me know what you think, and thanks!
From what I've read, no oil pressure is oft times a sending unit failure. I'll be replacing it just to make sure that it isn't the problem.
I've also seen that the idle problem could be due to leaking vacuum lines, however, everything I've seen on that is related to TII, and this one is NA. Could this still be the issue?
The worst-case-scenario center in my brain is worried that these problems are related -- that possibly something has gone wrong oil-wise (failed pump?) and the heat/not wanting to idle is due to lack of lubrication. Let me know what you think, and thanks!
03-10-10, 02:05 PM
#2
Typically if it will start, but then stall immediately if you don't give it some throttle, it's due to vacuum or metered air leaks. Vacuum leaks can be from uncapped/broken hoses, or old gaskets, etc... and they'll be anywhere past the throttle plates. Metered air leaks would be from between the throttle plates and the AFM, so the plastic air duct is the area to look for this. If you can keep it running long enough, you can spray some carb cleaner or something similar around the intake manifold. If the idle speed increases, you've found a leak.
0 oil pressure is bound to be a bad sending unit or the gauge itself. The manual has test for both of these. The cheap substitute for testing the gauge is a few resistors from Radioshack. If you hook these up to the wire that normally connects to the sender, then ground it to the chassis, you should get the needle to move.
0 oil pressure is bound to be a bad sending unit or the gauge itself. The manual has test for both of these. The cheap substitute for testing the gauge is a few resistors from Radioshack. If you hook these up to the wire that normally connects to the sender, then ground it to the chassis, you should get the needle to move.
03-11-10, 09:41 AM
#3
Junior Member
Thread Starter
Join Date: Mar 2010
Location: California
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
after searching around a little bit, I happened across this thread which may, indeed, be my problem (bad AFM). To test this, a couple of people mention jumping the fuel check connector. How would I do this?
03-11-10, 08:13 PM
#4
Junior Member
Thread Starter
Join Date: Mar 2010
Location: California
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
searched around some more and figured it out. Jumped the connector and it idled, roughly, but it idled. Looks like AFM is the issue. Now to find another one...
03-11-10, 11:19 PM
#5
Junior Member
Thread Starter
Join Date: Mar 2010
Location: California
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
Did a poor man's vacuum line check with the AFM disconnected and the fuel check connector jumped. Sprayed some carb/choke cleaner around the lines while it idled, and didn't note any changes at all.
(also, let me know if multiple update posts in a row like this are frowned upon here)
(also, let me know if multiple update posts in a row like this are frowned upon here)
Trending Topics
03-12-10, 01:06 PM
#8
I'd say you're on the right path. The AFM has a fuel cut switch that will cause the engine to start, then immediately stall if bad. Start up fuel is independent of the AFM circuit. Try propping the door open on it, then starting the engine. If it idles, this will just back up your diagnosis of a bad AFM. Also, the FSM has resistance values for each of the pins on the AFM connector. The fuel cut switch should basically show 0 resistance with the door closed & infinity with it open.
And posting updates is perfectly fine. It's your thread, so you can do just about whatever you want
.
And posting updates is perfectly fine. It's your thread, so you can do just about whatever you want
.
04-07-10, 01:40 PM
#9
Junior Member
Thread Starter
Join Date: Mar 2010
Location: California
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
SO! Got a new AFM installed, and the car now starts and idles. Plugged the oil sending unit back in (yeah, it was unplugged) and oil pressure is fine.
I'm still having a couple of problems -
1 - It seems to be running rich, and I'm not sure what would cause this.
2 - Surging idle. It won't sit down. It surges between 1600 and 1900 constantly.
Any ideas?
I'm still having a couple of problems -
1 - It seems to be running rich, and I'm not sure what would cause this.
2 - Surging idle. It won't sit down. It surges between 1600 and 1900 constantly.
Any ideas?
04-08-10, 08:41 PM
#11
Junior Member
Thread Starter
Join Date: Mar 2010
Location: California
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
figured this out as well! Its my TPS. Unplugged it and the engine idled perfectly. Time to flush the cooling system and replace my waterpump and thermostat.
04-09-10, 01:55 PM
#12
Try adjusting the TPS: http://howto.globalvicinity.com/gv_w...i=58&co=1&vi=1. The pictures in this writeup are gone, but terminal "A" on the 3 wire TPS plug is the important one. This will be the wire on the top of the triangular plug. Measure voltage between this wire and a ground source. With the engine fully warm (but not necessarily running. The key can just be in the 'ON' position), adjust the TPS screw until voltage is 1.0V. If the resistance sweep has dead spots, or resistance values are just wrong, a new TPS may be in order too.
Thread
Thread Starter
Forum
Replies
Last Post
