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TrxPipUK

1992 350D Starting problems

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18 minutes ago, shadetree said:

fuel pump oem ?, fuel pump getting enough fuel ?, fuel cut-off relay working ?. air filter new ?. these carbs MUST have a restriction in order to get the correct amount of fuel to the intake. try removing the fuel line from carb/pump, attach a short line in its place, fill the carb up until line is full, crank it over, if it fires and runs this way ?, this is a fuel delivery issue, if it does not ?, then its an engine problem, maybe spark ?. I do know this...if the fan control unit is bad ?, it will not spark correctly !.

Hmm okay... I'll try that filling the carb up trick and get back to you... 

How can I check to see if the fuel cut off is working properly? Also the fan control unit, is there a way to test that as well? Does the manual cover ways to test the control units?

Thanks shade

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1 hour ago, TrxPipUK said:

Hmm okay... I'll try that filling the carb up trick and get back to you... 

How can I check to see if the fuel cut off is working properly? Also the fan control unit, is there a way to test that as well? Does the manual cover ways to test the control units?

Thanks shade

if the fan control is bad ?, you will not get a consistent spark. no way to test it. service manual explains how to test the fuel cut-off relay. 

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He had it running shadetree, just having problems with the carb (sounds like he got ripped off on a fake Shindy kit) as far I know.

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Hi guys.

 

Got it running again. Think I must have flooded it yesterday some how. 

 

It is however still running quite rich... I'm thinking that there might be an issue with the fuel cut off relay not telling the pump to shut off when the carb is full as the pump is always on. I don't know if the pump is meant to shut off now and then so the carb gets just enough fuel or what? Could the pump being on all the time mean that it's always just pushing way too much fuel through the carb? 

Just a thought, probably silly one lol

 

What does the fuel cut off relay actually do in terms of how it controls the pump? 

 

Thanks 

 

Pic of the spark plug. What do you think about the colour? Look okay or too black? Looks pretty black to me

20210106_163732.jpg

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looks on the rich side, but clean the plug, and try it again,and your correct the fuel pump should not be pulsing all the time, unless the tank is about empty, or is empty.... it should pulse every fews seconds ..... if working correctly 

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1 hour ago, _Wilson_™ said:

looks on the rich side, but clean the plug, and try it again,and your correct the fuel pump should not be pulsing all the time, unless the tank is about empty, or is empty.... it should pulse every fews seconds ..... if working correctly 

Okay. I'm fairly positive that it doesn't do this. How is the pulsing controlled and how does the pump know what to do?

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3 hours ago, TrxPipUK said:

It is however still running quite rich... I'm thinking that there might be an issue with the fuel cut off relay not telling the pump to shut off when the carb is full as the pump is always on. I don't know if the pump is meant to shut off now and then so the carb gets just enough fuel or what? Could the pump being on all the time mean that it's always just pushing way too much fuel through the carb? 

 

Yup its running quite rich. The fuel pump relay has nothing to do with it.

 

There is a pressure switch on the end of the fuel pump that shuts down the pump when fuel pressure reaches about 2-3 PSI. That pressure switch is not working. You may be able to fix it after taking the end cap off, but more than likely its done. You will probably need a new (or good used) fuel pump.

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They've boosted the price of those fuel pumps by more than USD $50. Thats outright gouging man....

PUMP, FUEL 16710-HA7-672

 

I would not give them a nickel they're criminals. I would try to fix the pressure switch and if that weren't successful I would add an aftermarket  pressure switch to the outlet and use that pump. But thats just me....

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Do this first:

Unplug the vent hose from the end cap of the fuel pump, make sure that that hose nipple is clear, then start the motor. If the pump then shuts itself off like it is suppose to then the vent hose is clogged. That vent on the end cap must see atmospheric pressure in order to allow the pressure switch diaphragm to work.

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Thanks @retro really appreciate it.

I'll check it all out and look into it. A new oem pump here is £160.. ouch lol. That's a lot.. 

 

On 1/6/2021 at 9:19 PM, retro said:

I would add an aftermarket  pressure switch to the outlet

How would I go about adding a pressure switch? What kind of thing do I need to look for? 

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1 hour ago, TrxPipUK said:

How would I go about adding a pressure switch? What kind of thing do I need to look for?

 

I don't have any particular switch in mind... I'd either search & find one that might work or I'd build my own pressure switch. But that may not be necessary....

 

If I remember right the end cap on the fuel pump can be removed by taking a screw out. So you should be able to remove the pump from the mounting bracket then remove that plastic end cap very carefully.... take a photo of the end of the pump once ya get that cap off, and we'll see if we can fix it?

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I bought new OEM fuel pumps for both my quads. You can try to rebuild them but there’s a mechanical relay that wears, a gasket that stiffens and leaks. I have a leaky one that i can open up and post pics, but if you really think it’s the fuel pump, buy a new one. Dang it they’re 30 years old now you’ll need a new one sooner than later—price sure won’t go down wot wot?

 

pip are you absolutely certain you’ve nailed the carb synchronization and air/fuel mix? Cause if you’re not sure ... a fuel pump causing a rich mix? Not the prime suspect in my book.


I replaced the carb float in one of my carbs because it didn’t pass that test in the manual. 

Edited by Goober
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As I recall you said when you turned the pilot screw until it seated, the engine stayed running. Is this still so?

 

did you replace the choke valve?

 

 

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Thanks guys! Sounding to me like the best option here would be to get a new pump. Is it a really bad idea to get a Chinese pump and see if it solves the problem with that? Then it definitely tells me it's the pump issue and not the carb or whatever. And if it's not the pump then I've only wasted £15.

I know it's never good to get Chinese made crap but for test purposes? 

 

22 hours ago, Goober said:

As I recall you said when you turned the pilot screw until it seated, the engine stayed running. Is this still so?

 

did you replace the choke valve?

 

 

Yes that was the case. I haven't tried seating it in all the way again but at the moment its only one turn out and still rich. 

Is the choke valve the metal piece with the sharp needle on the end on the choke cable? No I haven't replaced this but it does have a fresh seal on. 

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Well, you have already learned that the fuel pump is not shutting off and that fuel is being forced past the float valve due to excessive fuel pressure. China pumps are garbage, a waste of both your time and your money. So your options are either replace the fuel pump with am OEM Honda part or repair your existing pump.

 

If ya want to tinker a bit you may be able to take the end cap off of your pump and fix it well enough to prove that it is over pressurizing the fuel. That shouldn't cost ya anything more than your time if successful. You could then invest in an OEM pump and solve the problem for good..

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57 minutes ago, TrxPipUK said:

Is the choke valve the metal piece with the sharp needle on the end on the choke cable? No I haven't replaced this but it does have a fresh seal on. 

 does that enrichment valve that you installed a new seal on , slide smoothly , but snug into the carb and not wiggling around in there ?  maybe buy a new one with the seal already installed ----you got a pic of that enrichment valve with the new seal in place ? 

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Hi Pip,  I don't know if you have discount tool places like Harbor Freight in the UK, but I have a cheap fuel pump pressure gauge I bought from them years ago for about $10.https://www.harborfreight.com/fuel-pump-and-vacuum-tester-62637.html  I also thought my fuel pump on my 350 might be over pressuring the carb. I put a temporary "T" in between the pump and the carb and checked it. It was perfect. After much trial and error, I narrowed it down to the choke enrichment plunger. I had replaced the seal on it with one from my K&L carb kit, so I figured I was good. Turns out that the rubber seal at the bottom around the little pin was hardened and shrunk. I bit the bullet and bought the new OEM plunger assy and my carb problems were solved immediately. Do not underestimate the effect of an old plunger especially at idle. I would buy or borrow a fuel pump gauge instead of a Chinese fuel pump...

Edited by Howols
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Hi everyone. Sorry for being so in active, been kinda busy lately. 

 

Just read what @Howols has said there and thinking maybe a new choke valve plunger is what I need next. I think something must be up with the choke because it still doesn't shut off when the pilot screw is seated. 

 

If the pump is just constantly pumping then surely that would just mean the carb would overflow and not effect the the amount of fuel going to the engine at all. 

 

The next step I think will be getting the choke valve out, check that rubber seal at the bottom and get a few pictures for you guys to have a look at. 

 

On 1/11/2021 at 2:26 PM, Fishfiles said:

does that enrichment valve that you installed a new seal on , slide smoothly , but snug into the carb and not wiggling around in there ?  maybe buy a new one with the seal already installed ----you got a pic of that enrichment valve with the new seal in place ? 

Yes it all moves nicely fish. I'll get a pic or two when I get a minute. 

 

Thanks all

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On 2/3/2020 at 12:26 PM, F250 guy said:

Was that cold or warmed up? You gotta have it warmed up so everything will be tight when ya do it. Try warming it up real good and reporting back. 😁

Wilson, what I meant was for him to see if the compression raised when it was hot and if so how much. 

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On February 3, 2020 at 11:26 AM, F250 guy said:

Was that cold or warmed up? You gotta have it warmed up so everything will be tight when ya do it. Try warming it up real good and reporting back. 😁

 

On February 3, 2020 at 12:25 PM, F250 guy said:

Was trying to help.

 

On February 3, 2020 at 3:12 AM, TrxPipUK said:

So I've done a compression test and the results didn't look to promising.... I got a result of 50psi. I'm yet to check the timing but I guess it's probably a the valves or piston rings? 

Thanks 

 

i  think you meant to quote @TrxPipUK but why from page 5 ?  pretty sure this was coved a few pages back.

Edited by _Wilson_™
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Hate those things.  We didn't have them here before that big 2011 flood.  Guess some floated in then.

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Oh yeah.  We've had dillas for a long time.  Fire ants were new though.  Hate both of them!

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