Possible stuck open injector??
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Possible stuck open injector??
New member here, I’ve got an 86 f.150 2wd with the 302. I bought the truck and immediately loved the power it had, well two days later I go out to start the truck and it’s running like **** and smoking. Head gasket is fine so I’m swap plugs no effect, so I do cap rotor and wires... no effect. So I take it to a shop they put on a new iac valve and new in-line electric fuel pump and fuel regulator. I get the truck back and it’s still Running wayyyyy to rich and idleing like **** but when your driving and give it gas it runs great and fast as all hell. So now I’m thinking maybe an injector is stuck open and just constantly pumping in fuel, is that even a possibility, how can I check them and make sure?
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the truck does run very rich and very poorly, when it first happened I swapped the plugs but didn’t pay much attention to them, the currant plugs have been in it since right before I took it to the shop so I guess I’ll pull them and see if any are black and gunked up, and of so I’ll just replace that injector and see what happens
Lead Driver
Joined: Sep 2003
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From: SoCal
Definitely check the plugs for one that's black or wet with fuel.
Put a pressure gauge on the Schrader valve on the fuel rail and turn the key on. The EEC will run the pump for a couple of seconds to pressurize the lines. The pressure should hold at about 40 psi on the gauge. If it drops, there is a leak, but that could be an injector or the regulator. I've actually heard a leaky injector before.
You might be able to borrow a gauge from your local auto parts store. If not, they're cheap to buy from many sources.
Put a pressure gauge on the Schrader valve on the fuel rail and turn the key on. The EEC will run the pump for a couple of seconds to pressurize the lines. The pressure should hold at about 40 psi on the gauge. If it drops, there is a leak, but that could be an injector or the regulator. I've actually heard a leaky injector before.
You might be able to borrow a gauge from your local auto parts store. If not, they're cheap to buy from many sources.
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I’ve got a fuel pressure gauge so I’ll definitely do that first, but the in line pump that would normally run for a few seconds doesn’t shut off it just keeps running so I’m guessing it’s because an injector is broke and won’t pressurize and just dumping all that fuel down the cylinder.
Lead Driver
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From: SoCal
The 2 second run at key-on is not dependent on pressure; it's just a pre-programmed function, with no feedback. So if the inline pump is also controlled by the EEC, then something is not working properly. This may be related to why the engine is running too rich. How do the plugs look after a run?
FTE Legend
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From: Ottawa, Ontario
A fuel pump that runs constantly is a classic sign that the PCM is failing, that would also explain the poor running condition.
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So I decided too follow the red power line coming off the online pump that was just replaced by a local shop to discover they ran the line to the fuse box and just shoved it in with a fuse...doesn’t take a genius to know that’s wrong and I wonder if that could also be part of why the pump doesn’t shut off when the key is on but not running. Obviously I’ll never take another vehicle to said shop as this is one of many **** ups of theres I found after they had my truck for a month
Fleet Owner
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From: Kentucky
There was absolutely no reason to run a new power feed. It was a plug-n-play job to install a new external fuel pump. Morons for sure which now adds more mystery to your overall rich condition. See if the ham fisted monkeys left the original power feed plug in place. If they cut connectors now you have to further jump through hoops to fix their mistakes.
The other thing to now verify is fuel pressure. If they installed a fuel regulator for a 6 cylinder engine your fuel pressure is too high.
The other thing to now verify is fuel pressure. If they installed a fuel regulator for a 6 cylinder engine your fuel pressure is too high.
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UPDATE
So I have correctly re-wired the in-line fuel pump, took a whole ten minutes haha and the pump now comes on for 3-5 seconds and then goes off as it should!! The trucks still running kinda crappy so I’m gonna replace the fouled plugs and still probably replace the injectors, I’m also got a brand new distributor just in case
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I have not pulled any codes yet, this is my first older vehicle that does not have an obd2 port so I don’t know a lot about how to read codes on this 86. Minutes know there’s a port under the hood near the battery and that codes can be pulled I just haven’t learned how yet
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Update
So I pulled all my plugs and cleaned them with brake cleaner and reinstalled them and immediately the truck is running soooo much better, but still isn’t there it seems to lack power and miss when I give it gas I assume the truck is out of timing and that’s what I’m gonna start with since I’ve already ordered and received a new dizzy anyhow may as well put it in and time it and hopefully I’ll have it running nice and smooth again. Also replaced all the dash bulbs which was a bitch and a half but also gave me a chance to fix the gear shift indicator so win win
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