FourEyed5Oh

hey guys.. so heres my current issue.
i own a 1986 5.0 fuel injected mustang.
i recently replaced the fuel tank, all new lines, new filter and upgraded to a 155lph fuel pump. The car runs fine when its cold. Once it starts warming up and runs for about 10-15 min it starts surging at idle. The rpms drop down so low that if i dont give it gas it will stall out. Before i did the tank i had done the upper intake manifold last year so im pretty sure a vaccum leak is not my problem. Also i cannot find any wet spots on the newer lines so im also pretty sure there isnt a leak. there is a plastic vent elbow that comes out on the top of the gas tank, i hooked the line for the charcoal canister to it. Im not sure if this is correct placement but it seemed right when i hooked it up at the time. i checked the EGR Vacuum Solenoid part # FORD E53E-9J459-AA , it was my understanding this controls the cars vaccum at hot tempetures, when i went to remove the plug looked like it was dam near melted, super crusty and white looking on the inside, so i replaced the plug with two pigtail connectors and i still get the surge at idle. Also once the car warm and is surging at idle if it dies out its impossible to start. The started wont engage at all if the car is not running but the engine is warm. It just makes a spinning noise like the bendix spring isnt grabbing correctly. my question is where do i go from here.. i put fuel injector cleaner in thinking maybe i had some clogged injectors that couldn't keep up with the newer fuel pump the car seemed to idle smooth when cold but once i took it around the block and got it to operating temp it began surging again. i can get a set of bosch 24lbs injectors that are rebuilt with 0 miles on them for $100 obo but i dont wanna drop that much money on a what if problem. I still need to replace the shocks because i got a set of 275/50r15 (might be off but theyre like 28x10s) mickey thompson street slicks for the back and they rub in the rear on the outside wheel well. not to mention the front shocks are completely shot so i would like to fix the surging issue as cheap as possible. thanks in advance for any tips or suggestions cause tbh at this point im lost

dawson1112

We need to determine what is keeping the car from starting once it dies out.
Is it fuel pressure , or spark? I wonder if your not pulling vacuum into the fuel tank and preventing the pump from doing its job. Try running it with the fuel cap off for a bit and see if it still does it.

88 orangepeel notch

+1 ^^^

And skip the 24# injectors, they're not needed or the problem.

Take the starter in to your local parts store chain, and have them test it. But it'll probably work perfect for them being it's not hot. I'd just replace it "IF" your sure all the connections were clean and tight.

Start looking for a vacuum leak, make a DIY smoke machine if your ambitious. Google/YouTube will show you how. They will pin point any leak you have. Any small vacuum leak plays havoc on the idle in these cars.

FourEyed5Oh

thank you for the replies. The issue i have now is when its cold it wont start either, the starter just makes a whirling/spinning noise. i jumped the solenoid on the fender wall and it did the same exact thing. I checked the battery with a load tester and it shows 12v with no load on it, once i apply the load it drops down to 10v / 200-400 cranking amps. i hooked the battery charger to it and still the same the starter just makes a whiriling/spinning noise. I noticed reman starters at mustangs unlimited are only $65 (after the core charge) and the valucraft from autozone is $49.99 , with the duralast being $62 dollars. I dont really wanna break the bank on it as i have already put a ton of money in the car this last month so if i do end up having to buy one out of those 3 which would you guys recomend??

mjr46

if your 86 is speed density you don't put anything other than 19 lb inj's in them or you'll begin to cause other issues...if it's mass air converted, you'd also need a maf for such.

mjr46

if the starter is spinning but the motor is not turning over, your bendix is bad......= new starter and I wouldn't use any of those junk starters....I'd convert to a 92 style starter = high torque mini.......slightly more expensive but they work so much better.....the cheap vatozone starters are just that....you'll be doing another soon for 49.00 beans.

FourEyed5Oh

i was also looking at the mini high torque starter from mustangs unlimited, the one that is $120 but i found good news. I went to remove my old starter today and found it was barely attached to the vehicle. The prev owner replaced it and it looks like he just never bothered to put the top bolt in. I put a new bolt in tightened it down and viola the car started like normal. i ran the car to operating temp (dont have a gauge so i let it run for about 10-15min) with the gas cap off the whole time, as the car got warmer the surging got worse. when i give the cart throttle it almost seems to like clear out but then drops back down in idle. i did notice when i pump the brakes the car mantains a idle of around 1100 rpm and doesnt surge down. i set my timing in november before winter to i think 10* tdc. if i remember correctly. the car has a new brake booster and the hose that attaches to the 4way plastic peice on the firewall is also new. i was told the egr vaccum solenoid that i mentioned in the prev post is what controls the cars vaccum as it warms up, but other then that im going to attempt to make a diy smoke machine cause im guessing its a vaccum leak now. not sure if this matters but the car idles near perfect when its cold once it warms up is when i get the issue.

mjr46

egr selonoid does not control vaccum as car warms up....egr should only be active at light cruise speeds.

FourEyed5Oh

ayye we fixed it... lemme go into more detail, so on a whim i unplugged the charcoal canister line from the vent elbow on the tank, the car car idles fine now, upon further investigation i found the line for the charcoal canister comming off the intake is plugged up and there is no charcoal canister on my car at all. i dont belive this is a issue because i dont need to go thru emissions but the car is idling near perfect now. a freind is comming over tomorrow am to help me reset the timing as the car seems to be running a little rich but other then that it seems good. im also having issues with the gas gauge and brakes (cant get new proportioning valve adjusted right) but i will start a new thread for those. thank yall for your help.

dawson1112

so you were pulling vacuum in the fuel tank?