109 exmod gremlins are back

[siii8873]

well he's back. Truck has run flawlessly since replacing alternator about 3 weeks ago in NC. Well today some old issues raised their head again. First went to start truck, turned over would not fire. Has not done this for about a month. I poured a little gas in carb it fired and started. Drove to work, shut it off, started fine. Drove about 1.5 hrs to a job site, stopped and got gas on way started fine. While at site had to move the truck, it started drove about 50yds, it stalled and would not start. A little fuel, took 2 times this time, ran fine. stayed about another hour and went to start it no go. Took many times to get it going this time. Once it starts it runs great! Things I have worked on/replaced in last month, New plugs,points condensed, cap,rotor, wires, fuel pump.
One other item. After I was on the road for about an hour my turn signals stopped working. They started working again when I started home, quit again for a while after driving for a while, then worked again. Not sure if it's related. This one has me stumped. I'm thinking it could be electrical but what is the fuel doing to make it run if so? Any thoughts?

[bkreutz]

Could be a fuel pump issue. Perhaps the fuel is siphoning back out of the carb after it sits for a while, then when you crank it, you're not getting enough pump action (slow cranking speed), when you add fuel, it starts and the pump is pumping much faster. Could be a loss of spark too, but adding fuel to the carb wouldn't have any effect.

[siii8873]

Forgot to mention I replaced the fuel pump also. I also thought it was a syphoning problem after sitting when this was going on a month ago or so. Then it seemed to happen only when it sat for a while. Today it did it after sitting for less than an hour. It also started drove for about 50yrds stalled and wouldn't start.
The carb is a weber 34Ich, are these symptoms of a dirty weber?

[bkreutz]

IMO a new pump is not necessarily a good pump (that's why they have warranty's) One quick way to check if the float bowl is empty is look down the throat and operate the linkage by hand, if there's fuel in the bowl the accelerator jets will squirt fuel. Could be something plugging up the carb internally, but if the carb fails the "squirt test" I'd be looking at fuel supply.

[hughwilton]

I got a couple of bad fuel pumps in a row. I now have an electric fuel pump & have not had any fuel issues for over 4 years. (I'm running a Rochester).

[siii8873]

what confuses me about this is after it starts it runs great. No hesitation great power, no problems. Maybe I'm all wet but if it were a fuel supply problem wouldn't I have operation problems when running.

[o2batsea]

Original carb? If so it's probably time for a new one. Rebuilding is a waste of time. You might also consider fuel injection.

[jac04]

^^He stated he's running a 34ICH, so it's not the original carb.
Fuel injection? Really? Let's try to offer him some more feasible solutions to his problem.

Back to the fuel problem.....
Are you still running the twin tanks with the changeover valve? Check out the valve - sometimes they can allow air to enter the fuel system without showing signs of leaking.


One other item. After I was on the road for about an hour my turn signals stopped working. They started working again when I started home, quit again for a while after driving for a while, then worked again. Not sure if it's related. This one has me stumped. I'm thinking it could be electrical but what is the fuel doing to make it run if so? Any thoughts?
I had the same issue with my Lightweight signals. Turned out to be a broken connection on the flasher relay circuit board. A quick touch with the soldering iron fixed it.

[bkreutz]

what confuses me about this is after it starts it runs great. No hesitation great power, no problems. Maybe I'm all wet but if it were a fuel supply problem wouldn't I have operation problems when running.
Not necessarily, think about the speed of the fuel pump while cranking and then think about the speed while idling, big difference. Sometimes (notice I said sometimes:D) when a pump is starting to fail, it will not pump at slow speeds but at a faster speed it will pump enough to mask any problems. May be wrong, but I've seen this scenario before. Keep plugging away, you'll find it, after all it's only a machine.:thumb-up:

[singingcamel]

i have a hunch its in the carb,dumping the fuel down it is just like priming a pump..Stuck float , bad accelerator pump..change your fuel filter .
www.singingcamel.com (http://www.singingcamel.com)

[siii8873]

I have a spare, with a service kit rebuilt / cleaned 34ich with correct jetting and thinking just change it and wait and see............... Fairly quick and easy.
I did change the filters a short time ago including the one at the carb inlet. I'm leaning toward this being the issue also.
Just always hear from everyone fool with carb last.

[o2batsea]

^^He stated he's running a 34ICH, so it's not the original carb.
Fuel injection? Really? Let's try to offer him some more feasible solutions to his problem.

Back to the fuel problem.....
Are you still running the twin tanks with the changeover valve? Check out the valve - sometimes they can allow air to enter the fuel system without showing signs of leaking.


I had the same issue with my Lightweight signals. Turned out to be a broken connection on the flasher relay circuit board. A quick touch with the soldering iron fixed it.
Yes, genius, fuel injection. Don't be scared of it.

[jac04]

^^Thank you for referring to me by my proper title, although the "G" should be capitalized. :rolleyes: Anyhow, I (and quite a few other people here) would be interested in your 2.25 fuel injection set-up. Feel free to start another thread on the subject.

Given the problem at hand, suggesting a custom FI installation as a solution is just a little off target, don't you think? And suggesting that an original carb be discarded & replaced just because "it's time for a new one"? To each their own I guess.

[SafeAirOne]

Anyhow, I (and quite a few other people here) would be interested in your 2.25 fuel injection set-up.

There are quite a few 2.25's out there with factory fuel injection. My 2.5 is fuel injected.





;)

[daveb]

really hard to make a meaningful diagnosis without more information. when the truck wont start, can you check to see what other things are working? That might help to rule out an electrical problem. it does sound a bit too intermittent to be a fueling issue. Check your ignition switch and fusebox.

[lrover109]

When I had a similar issue with my MOD the problem was in the fuel tank switch - took it apart and the gasket had broken down made a new one and it solved the problem.

[jac04]

There are quite a few 2.25's out there with factory fuel injection.
Great. Didn't know that doing a FI install on a 2.25 was simply a matter of installing some factory parts.
Anyone got as list of what parts I need?

[Terrys]

Yeah Jeff, Just what the LW needs "Once You Go Diesel, You Stink Like A Weasel"

[jac04]

^^Maybe I missed something. I thought we were talking about a petrol FI setup, since the OP has a 2.25 petrol. Diesel - no thanks.

[SafeAirOne]

Great. Didn't know that doing a FI install on a 2.25 was simply a matter of installing some factory parts.
Anyone got as list of what parts I need?

Yeah..I was just being a wiseguy about the diesels already being factory fuel injected.

Getting back to reality and the OP--Something odd about it being an intermittent problem that is being cured (most of the time) by putting some gas down the carb and then having it run flawlessly thereafter. I'd expect that sort of thing to happen all the time, not intermittently.


Have you checked the fuel level in the bowl to see if it's leaking away or if something else strange is going on in there? Even still, I'd expect the pump to refill the bowl in enough time to start up during cranking...

[jac04]

..I was just being a wiseguy ...
(Moe voice) "Oh, a wise guy, eh? Why I oughta..."

Sorry, the heat must be affecting my sarcasm meter.

[siii8873]

Jeff (alias Genius), and larover109 I'm very sure it is the fuel tank switch. I had a spare fuel line so I connected the right tank straight to pump (taking switch out of line) has started ever since. Took valve apart and gasket/seal quite dry and cracked.
Looking for new gasket.
Guess which tank was full!
thanks
Bob

[o2batsea]

Although this site (http://www.affordable-fuel-injection.com/) sells many new parts, really the heart of the conversion is the TBI to one barrel adapter. With that you can source a Rochester TBI from any of the thousands of 80's vintage GM 4-6-8 cylinders along with the ECU and harness, an electric fuel pump and away you go. I think with a little creative scrounging one could have EFI on the two and a quarter petrol for only a couple hundred bucks, or less. If one absolutely HAS to have all new I think it could be done for about a thou, but probably less.
I have retrofitted several Chevy marine engines to EFI and one Ford V8. I also started to do the IH 345 but dropped that project. It's all pretty simple stuff and once you get rid of the carb you will have better drivability.

At my nudging, TeriAnn converted her Ford V8 to EFI and has never looked back. Both Ford and GM spent tens of millions developing reliable EFI systems for their cars. Why not take advantage of that?

[siii8873]

well truck is starting fine since I bypassed change over tap. I have found a replacement gasket but not on top of priority list to put it back in service.
Turn signal problem went away for weeks on its own. Until today quit working again. Related question? On the exmod the Tex Magna unit has a bulb that indicates the turn signal. There is also an amber indicator light on the dash panel with the lighting switch. From looking at the wiring diagrams I'm thinking this light should only light when a trailer is connected to the wirirng. Is that correct? I ask because on occasion this light lights up with turn signals, not very often. Genius indicated that he had a similar problem with intermittant turn signals which was in the EXMOD relay. I'm thinking this could be same given this second indicating light flashiing on occasion.

[Les Parker]

Either a ground or that loverly MOD Hella flasher unit has a "hot" spot on it.
Easy to fix if the board has a dry connection.

[akrvr]

I had a similar problem with my exMOD. New fuel pump. I bought the new style from RN. The hand lever worked when pumped but it would not work when the engine was cranking. I installed an electric pump and end of problem! Good luck!

[siii8873]

well I think I have everything working (except dual tank switch just havn't got to it) Spent 2 hours looking into the problem. Was trouble shooting with a voltmeter which can fool you. Was getting 12 volts to the #1 terminal of the 6way switch. After finding nothing I put a test light on the terminal and no light. It was the supply to the switch at the terminal block. Renewed that connection all good.

[siii8873]

well I thought I had this problem licked, NOT! The lights worked fine for about two weeks after renewing the connector. On Thursday the precurser started, yellow turn indicator on dash panel started flashing again with stalk light and then lost turn signals again. They started working again with the yellow indicator on dash flashing also.
I do have one question, should the dash light be flashing with the turn signals? Or should this flash only when a trailer is hooked up electrically?
Think I need to check out the military relay as suggested earlier.

[jac04]

They started working again with the yellow indicator on dash flashing also.
I do have one question, should the dash light be flashing with the turn signals? Or should this flash only when a trailer is hooked up electrically?
Think I need to check out the military relay as suggested earlier.
The yellow light is only supposed to flash when a trailer is hooked up electrically. I'm not sure how the vehicle "knows" when a trailer is hooked up. On my Lightweight, the yellow light flashes along with the green turn signal indicator at all times. It has done this since the day I bought it. I looked at the wiring diagram once to try to figure it out, but gave up quickly since it didn't appear to be an issue.

[disco2hse]

The orange/yellow light should only flash once if there is no trailer attached and continue to flash when one is. The green turning indicator flashes in both instances. If there is a failure in the circuit the green and orange/yellow will flash once only even though the flasher unit will continue to click. Note that this is dependent on which side the break exists. Break on left circuit and indicator lights will flash once only when indicating left, and vice versa for right.

The same rule applies to the trailer coupling circuit. When the circuit is complete (a trailer is attached and wired in) then the orange/yellow light will continue to flash. Breaks in the circuit on either left or right will exhibit the same results as above but only for the orange/yellow light.

If yours continued to flash Jac, then I would say that someone probably shorted the circuit to make something else work ;)

[luckyjoe]

When you refit the tank selector switch to your system, make sure all the compression fittings are tight. One of them just a 1/8-1/4 turn out and you'll prevent fuel flow...

[siii8873]

thanks, I have it installed working fine, except switches. the switches are a real PITA to install when the valve is in place on bulkhead. Fiddle with it, drop nut, crawl out from engine compartment, find nut on gravel drive, repeat, repeat...