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Hello everyone,
I am new here so hi.
I own Crescent city transmission and diesel in crescent city California.
I have a 1989 f150 with a 5.8L, C6 and 4X4,
i am having some issues with the engine dieing and check engine light flashing, when I went to pull the codes I can't find the sti wire ? I cut the harness back and its not there. So how do I retrieve the codes from it ? I can't drive it now because it won't even make it down the street. Just so you know about four months ago I changed the O2 sensors and complete tuneup so it would pass smog witch it did. Last month the fuel pump went out and I changed it, it would drive about 20 miles and die and had no fuel pressure. After the fuel pump was in. it seamed to run decent but got worse in two hours. But it does start and run somewhat but the problem is definitely getting worse. Something else I noticed, there is a wire someone put on pen 5 off the EEC connect that runs over to the tps connecter, it's not factory so it alarms me as to why, maybe the tps is bad ? The harness other than that looks good.
I want to also do some upgrades to it in a few months like put a E4OD in it and I guess I will need to change the EEC and harness ? Any suggestions or parts ?
thanks Tim
Last edited by CCTV shop; 02-13-2017 at 01:00 AM.
Reason: Spelling
Hello again,
I read somewhere yesterday that if the 89 does not have a sti wire then I have to jump 2 pens in the EEC Sig Rtn to retrieve the codes ? Has anyone ran access this before ?
UPDATE: Ok after doing my homework and tracing out the wires I found,
The sti wire is there, it is just plugged into one of the main test ports,
so my codes are 23, 24 and 67. Witch is along the lines I was thinking
TPS. I neglected to mention that my neutral safety switch has been activg
Up, I have to put it in neutral to start it so I knew that too. I didn't know
that the air intake sensor had a problem too.
As for the red wire that someone jumped in, it goes from the coolant temp
sensor to the pen on the EEC connector, I took it off and the factory wire still
reads good.
Does anyone have any input ?
Last edited by CCTV shop; 02-13-2017 at 02:28 PM.
Reason: Update
On trucks, code 67 seems to refer to the A/C circuit but cars it refers to the MLPS (neutral safety switch).
The TPS is out of range - is it faulty or just out of adjustment. It should be at .9 volts exactly at closed throttle (and climb and fall steadily up to 4.5 to 5 volts as you open and close the throttle). That's on the signal wire. The other 2 wires are the power in (5 v) and ground.
Your ACT may just be faulty ? Fix the other problems first and see if the code comes back.
A brand new fuel pump makes you think there couldn't possibly be a problem back there anymore but that just isn't the case sadly. Some new pumps especially the cheaper ones just don't make it for quality. Plus you should have more than one pump on your truck - which one did you change ?
Your engine requires 30 to 45 psi to run, preferably you want to be in the 40 to 45 range.
Hi Chris and thanks for the information. 3 years ago I bought the truck for one of my sons, The tps was set at .4 at a idle so I bumped it up to .9 and it seamed to work fine however a month ago I noticed it started hesitating taking off from a stop, I checked it again and off a idle it seams to have a dead spot. I changed the front tank pump, The pump is a motorcraft I was thinking 40-45 psi also so as I get a brake I will check it. The back tank I will change when I get time. I want having trouble finding a wiring schematic for the backup switch or neutral safety switch, I have one for the E4OD and AODE with 6 or more pins and this one has only 4 pins it's a C6. 1989 f150 5.8L C6 4x4 XLT. I need to put my fuel gage on it here in a minute and see where it is , my guit feeling says it's running less than 15-20, I will get back
Good morning,
I have a new problem, the truck runs fine but park it and go to start it and the fuel pump has no power but there is power to one side of the relay but not power to excite the relay and I don't have a schematic for this truck yet so does anyone have a schematic ?
The schematic I found is for a 1989 f150 with dual tanks witch is what I have the thing I don't get is it shows a fuel pump in both tank witch I do have however it also shows a high pressure pump that I don't have. I was wondering if this could be losing current through the fuel tank selector valve
You should have a 3rd pump. The pumps in the tank are low pressure lift pumps, the high pressure pump should be on the frame rail roughly below the back of the cab.
They didn't switch to high pressure in tank pumps until 92 - ish.
They didn't switch to high pressure in tank pumps until 92 - ish.
Actually they started putting high pressure pumps in the tanks and completely eliminated the high pressure frame rail pump starting with the 1990 model year. This is one thing they didn't wait with until the body style change.
02-13-2017, 12:48 AM
1989 f150 with No EEC STI wire for pulling codes
