Engine Dies Randomly

[86'HPSi]

Haven’t been on in awhile. New issue arose with the Prelude. Car dies while driving down the road randomly.

Last year in the summer I put new injectors, distributor cap and rotor, wires, plugs.

To start, I did the fuel pump. Still dies.
I got another filter but haven’t put it on yet. Gas cap is fine and is holding suction while the pump is running.

Did the fuel filter 3-9-2022 and has ran fine, until now 3-14-2022. Cleaned the throttle body and no vacuum leaks that I can spot as well, followed all the hoses and where they connect. Also, I have not pulled out the EGR Valve if that would have anything to do with it. Nothing seems out of the ordinary. Still scratching my head.

[ShiRen]

Did you check the fuel pressure before you did the filter or pump? If it ran good after a filter I wonder if there is a lot of debris in the tank or lines. Maybe check the pressure now and then put another new filter in it or bypass it temporarily and see if it increases. Or just straight up drop the tank and peek inside.

[86'HPSi]

I didn’t check the pressure at all. I’ll look into it and also see if the fuel pump is getting the right voltage as well as drop the tank and see if there’s anything in there. Thanks for the response.

[86'HPSi]

Well I dropped the tank and put new fuel lines on, she was like new when I peeked inside. Fuel pump stopped sucking air. Haven't checked the fuel pressure.

Still will turn on then die, and or turn on and get a couple miles down the road and she dies, and I'm able to get it back on to make it to where I need to go and back home.

My only guess now is the Fuel Injection Pressure Regulator and or the MAP Sensor. $273.68 for both parts. Money isn't the problem, its putting on the parts and if it still does the same thing ; I'm feeling pretty defeated. At that point I'd rather sell it to someone who will appreciate it and get her running or make it their project car.

I've done all new seals and gaskets, oil filter housing gasket, front and rear seals, shift shaft seal leaks super slow, (except head gasket and intake and exhaust manifold gasket, cause theres no problems there), new flywheel and clutch, throwout bearing with cable, newer transmission, downpipe and catalytic converter and O2 Sensor, OBX Muffler, new rack and pinion with tie rod ends and upper/lower ball joints, all new bushings, CEIKA Coilovers Sport, new calipers and rotors, new brake booster, radiator, upper/lower hose, thermostat, timing belt, belt tensioner, oil pump, water pump, alternator, new belts, battery, plugs/wires/distributor cap and rotor, fuel injectors, fuel pump, fuel filter, air filter(s), Optima battery, Alpine receiver, JL Audio speakers, tires, drivers seat. Ive done it all except internals. And no, I dont ever dog the shit out of her, she's old. I got more sense than that.

With that being said, I'm gonna try a local guy who tests all the wires and will check the fuel pressure too, and if he cant find a problem I'm going to let her go.

[Dr_Snooz]

Randomly replacing parts is a pretty bad way to do diagnosis. Don't replace. Test. If you don't have the tools and manuals you need, spend money them instead. With a few simple tests from the Honda manual, you could have known for sure whether your pump needed replacing without the trouble of dropping the tank. You'll come out farther ahead in the long run spending money on tools and know-how you can keep, than on a bunch of new parts you give away in frustration.

In this case, you're the only person who can fix this. You need to pay attention to the car, though. How does the car feel when it dies? Does it sputter and chug, lose power and die slowly? If so, then that might point to a fuel delivery issue, like a malfunctioning injector. That might recall to mind that fresh gas smell you notice every time you turn off the car, for example, which would confirm your fuel delivery suspicions. It could also point to an ignition issue like a wire getting hot and losing connection. That might remind you of that crusty wire in your engine bay you've been ignoring, as another example.

If it dies real clean, like someone simply turned the key off, then that might point to something like a bad ignition switch. That might remind you of the heavy keychain the previous owner had.

The point is, there aren't easy answers on a 35 year old car. Only you know your car, only you can listen to what it is telling you, and only you can connect the dots. Tools, manuals and diagnostic aids will help you, but you have to do the detective work yourself.

Good luck.

[86'HPSi]

Randomly replacing parts is a pretty bad way to do diagnosis. Don't replace. Test. If you don't have the tools and manuals you need, spend money them instead. With a few simple tests from the Honda manual, you could have known for sure whether your pump needed replacing without the trouble of dropping the tank. You'll come out farther ahead in the long run spending money on tools and know-how you can keep, than on a bunch of new parts you give away in frustration.

In this case, you're the only person who can fix this. You need to pay attention to the car, though. How does the car feel when it dies? Does it sputter and chug, lose power and die slowly? If so, then that might point to a fuel delivery issue, like a malfunctioning injector. That might recall to mind that fresh gas smell you notice every time you turn off the car, for example, which would confirm your fuel delivery suspicions. It could also point to an ignition issue like a wire getting hot and losing connection. That might remind you of that crusty wire in your engine bay you've been ignoring, as another example.

If it dies real clean, like someone simply turned the key off, then that might point to something like a bad ignition switch. That might remind you of the heavy keychain the previous owner had.

The point is, there aren't easy answers on a 35 year old car. Only you know your car, only you can listen to what it is telling you, and only you can connect the dots. Tools, manuals and diagnostic aids will help you, but you have to do the detective work yourself.

Good luck.

Its a clean dying when she does, I'll be going down the road and because its in gear it sounds like its on, but its dead. When I take it out of gear it truly dies and I'll have to cycle the key a couple of times and it'll fire up and go and then just repeat.

I have a haynes and chilton manual, but when it comes to probing and testing wires, I dont trust myself to diagnose it properly when it comes to that. Its not my specialty, my Dad and I ran into the same issue with his 2011 Jeep Grand Cherokee Overland, we probed and tested all the wires we could and got the right readings and it turned out to be a bad fuel relay, cam and crank sensor, but when we tested them it was getting proper voltage. So, maybe you can see why I'd rather not mess with that situation with my car. Cause I wouldnt know any better.

I have a specialist thats going to look into that on 4-6-22. Im gonna run him through what it does and what I've done to try and solve this issue, same guy my Dad took his Jeep to.

I appreciate you encouraging me to know and understand my car more, but like the Jeep; I'm quite stumped on where to go from here. I've first thought it could be the filter and pump, the ignition switch, a fuse and or relay, etcetera. Ive done gone through all that and still the same issue again. At this point theres nothing more my books or tools or knowledge alone can do. That's why I'm sending it to someone who does it for a living, not my Florida-Georgia Redneck backyard mechanic self.

Thanks again Dr. Snooz.

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[ShiRen]

That sounds an awful lot like a loss of ignition, fuel usually drops in power first

[86'HPSi]

That sounds an awful lot like a loss of ignition, fuel usually drops in power first

If thats the case I'd rather send it to that specialist so he can fix it. Like welding, I can do it but it aint gonna be pretty you know. Either way, once its fixed I'll post the solution so other Do-It Yourself guys can possibly relate and pin their issue if it arises with the car. After all thats what the forums are for.

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[ShiRen]

These cars aren't complicated man... so far you have only been guessing and replacing parts instead of actually troubleshooting. I suggested you check the fuel pressure, which will pretty much rule out the fuel system entirely. For ignition Im going to also suggest you do the actual troubleshooting steps, its not hard, so why have somebody charge you out the ass to do it?

There are a few things you should look into for ignition:
Ignition tumbler. Has it ever not started when you turn the key? This can be no crank or no spark situation, doesn't have to be both. Can you pull the key out with the ignition is on? This doesn't mean its broke, just heavily worn. You ca also play with the harness under the dash, it could just need cleaned, bad connections are common there
Ignition coil. Do resistance tests on the coil. Make sure all your wires are good.
Distributor. Really the only thing you need to look at is the ignitor. I don't know the exact in pairs off the top of my head, but all you need to do is a diode test. An obvious symptom of a bad ignitor is a bouncing tach.

Since this is an intermittent issue, I don't suspect the coil and ignitor, unless your tach bounces. And I am not convinced this is an ignition issue, you should still check the fuel pressure.

[Oldblueaccord]

If thats the case I'd rather send it to that specialist so he can fix it. Like welding, I can do it but it aint gonna be pretty you know. Either way, once its fixed I'll post the solution so other Do-It Yourself guys can possibly relate and pin their issue if it arises with the car. After all thats what the forums are for.

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For free id run the car and bump the key a little and see if it shuts off. Mine will if I hit it with my knee going down the highway.

You can add a small 12 volt light to the fuel pump feed wire and see if its getting power back there also if you suspect its not.

If the ignition circuit is dead the tach wont read it goes to zero, it reads off the coil.



Here what mine sounded like when the fuel pump quit. I just put the original one back in it and got it running again.

[86'HPSi]

So last night I tested the Ignition (tumbler), and unplugged several connections of harnesses. The wires checked out, clean, no wear, and holding in the pins of the plugs. Im getting proper readings and continuity on all the wires there under the dash and Ignition. So, I feel safe to say the problem isnt there. However I wasnt able to test the distributor and Ignition coil, cause it got dark out. The wires and all are clean and firmly in the right positions.
With that being said, I fired her up (cha cha vroom) she ran and didn't die while sitting. The tach only bounces when I start it, its done that for the past 6 years I've owned her. When shes Idling or when I accelerate her while sitting, everything is normal. No bouncing of the tach when shes on. No, I couldn't pull the key out while she was on and bumping it didnt seem to affect it, I assume theres no problem there. However after work I'll test the ignition coil and the vaccum part of the distributor and see what voltage I'm getting.
The only thing I've noticed since this problem arose with the original fuel pump of 36 years and seems to be continuing with the new pump is that it doesn't always prime when I set the ignition to on. However while its running I can hear the pump running, but after so long of time and or several miles down the road she dies, the engine that is.
I'm going to check the fuel pressure but cant seem to find a schroder valve under the hood. So, should I just install a gauge into the fuel line for future reference?

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[Oldblueaccord]

So last night I tested the Ignition (tumbler), and unplugged several connections of harnesses. The wires checked out, clean, no wear, and holding in the pins of the plugs. Im getting proper readings and continuity on all the wires there under the dash and Ignition. So, I feel safe to say the problem isnt there. However I wasnt able to test the distributor and Ignition coil, cause it got dark out. The wires and all are clean and firmly in the right positions.
With that being said, I fired her up (cha cha vroom) she ran and didn't die while sitting. The tach only bounces when I start it, its done that for the past 6 years I've owned her. When shes Idling or when I accelerate her while sitting, everything is normal. No bouncing of the tach when shes on. No, I couldn't pull the key out while she was on and bumping it didnt seem to affect it, I assume theres no problem there. However after work I'll test the ignition coil and the vaccum part of the distributor and see what voltage I'm getting.
The only thing I've noticed since this problem arose with the original fuel pump of 36 years and seems to be continuing with the new pump is that it doesn't always prime when I set the ignition to on. However while its running I can hear the pump running, but after so long of time and or several miles down the road she dies, the engine that is.
I'm going to check the fuel pressure but cant seem to find a schroder valve under the hood. So, should I just install a gauge into the fuel line for future reference?

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There is a fuel pressure test port on the fuel filter at least on the accords. I got a pressure kit that goes on the filter as well.

[conozo]

When you crank your car to start does the rpms show around 1000 or does it jump to 5000 or 6000 when cranking.

[Dr_Snooz]

Your ignitor is definitely bad, and can definitely cause what you're dealing with, so replace that. Then throw out your Haynes and Chilton manuals. Get the OE Honda manual instead. The tests are all there and super easy to follow in almost every case.

1986 Honda Prelude Shop Service Repair Manual Engine Drivetrain Electrical Book | eBay

Get a printed copy so you can lay it out on a table and not have to fiddle around scrolling through pages.

[86'HPSi]

When you crank your car to start does the rpms show around 1000 or does it jump to 5000 or 6000 when cranking.

Around 1000.

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[86'HPSi]

Your ignitor is definitely bad, and can definitely cause what you're dealing with, so replace that. Then throw out your Haynes and Chilton manuals. Get the OE Honda manual instead. The tests are all there and super easy to follow in almost every case.

1986 Honda Prelude Shop Service Repair Manual Engine Drivetrain Electrical Book | eBay

Get a printed copy so you can lay it out on a table and not have to fiddle around scrolling through pages.

I actually threw out the haynes and chilton manuals, got on honda support and bought the service repair manual. Over 1,100 pages if I remember correctly. After pondering over the issue and reading more on here, I figured it would be best to have that manual and it's on the way.

Update : The Auto Eclectric guy, found that my main relay was the issue. So he opened it and was able to clean it and re-solder the small wires within and coated the little computer board in there with some electrical sealent, not nail polish. Also, replaced all my ground wires. Not that the connections were bad or dirty, but within the 36 year old wire casing, and the ends being exposed to the moisture and what not. The wires were corroding within the casing. 36 years and done, maybe not that long but needless to say, done.
So, $373 and the work that he showed me is pretty darn good looking. My car runs obviously, but for being in a bind with needing my car. The price seems fair for what he did. He ran all the new ground wires and my power wires. Tried it, it came on but would still die, then he ran the tests again and he got to the main relay, and rebuilt it, literally. Then here we are. Now that I have the real manual, I should be able to diagnose in depth and find the solutions, from here. Got to if i want her for as long as she'll go.

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[Dr_Snooz]

That's an unusual way for a main relay to fail. Glad you got it figured out. Enjoy your car.

[86'HPSi]

That's an unusual way for a main relay to fail. Glad you got it figured out. Enjoy your car.

Well, you said it best, The car is 36 years old and it could be one thing or a number of things. It gets pretty warm here in Southern Oregon in the summers and a mile up and down the dirt road I live on makes for one hell of a bouncy ride. I'm sure that doesnt help as well as all the dust. Im cleaning my car once a week its that bad in the summers.
Im loving it more and more everyday, can't imagine driving anything else.
Thanks again, sorry if I got you or Shiren up in arms over my ignorance.

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[ShiRen]

Thanks again, sorry if I got you or Shiren up in arms over my ignorance.

Youre good, I didn't expect the main relay, but I also forgot to mention it. I do hope you learned something though, I can say I have now lol.

[Mike's89AccordLX]

I will have to check out my main relay. I was getting a PGM-FI light and a #12 code. Checked the egr system and cleaned the vacuum stuff and the light went away. But the car will still stall out and it's exactly like you described above where there's no warning it just dies.

[Oldblueaccord]

I will have to check out my main relay. I was getting a PGM-FI light and a #12 code. Checked the egr system and cleaned the vacuum stuff and the light went away. But the car will still stall out and it's exactly like you described above where there's no warning it just dies.

its worth a try.

You can try re soldering the connections but its possible the relay itself is bad. I dont think new ones are too much.