Really High Idle at Start Up

Hello,

First off, this is my first post here! I've been reading several forums that have provided some great info about these trucks. I come today looking for some advice.

My 1989 Dodge ram 50 2.0L, 5Spd, factory mikuni carb is revving up to about 4K upon a cold start. Eventually she will idle back down, but it can take several minutes. I've had a friend who knows much mkore about these motors come take a look and he's done the following things:
1. Removed carb and cleaned.
2. Adjusted carb
2. Adjusted timing (by eye)
3. Cleaned distributer cap
4. Checked plugs & wires
5. Checked hoses

... and the problem persists! His final conclusion is that the electronic choke is bad causing the motor to rev so high when starting. And from what I can see and have read, this is riveted to the carb. Eventually the butterfly (in the carb) does back down, but like I said it idles ridiculously high for several minutes. The only other thing that was recommended for me to try was replacing the o2 sensor (which looks old).

I recently bought this truck and the previous owner said it had been sitting for about a year and that he noticed this problem from time to time (but trust me, it's every time the truck sits for more than 45 mins or so). The truck runs and drives great once the idle calms down. My only complaint would be that it holds onto the gas a bit longer than it should in between gears frequently (maybe a result of this funky carb?).

I've can't say that I've read too many positive posts about these mukini carbs and the Weber is a great replacement when the times comes - which sounds like now for me.

I'm trying to provide as much info as I know without going overboard. I'd like some thoughts that you may have around this problem. Much appreciated!

I forgot to mention it failed emissions. Unfortunately, I don't have the results from the test.

The high idol should be addressed first. You should see on the choke A high idle step cam where an adjusting screw Will sit on it and create the high idol. Move the butterfly valve for the choke and you will be able to find the high idle cam.

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Originally Posted by camoit

The high idol should be addressed first. You should see on the choke A high idle step cam where an adjusting screw Will sit on it and create the high idol. Move the butterfly valve for the choke and you will be able to find the high idle cam.

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Thanks camoit. So the high idle screw on the step cam is below the butterfly for the choke? I'll check this out when I get home. I know we adjusted all the other idle screws on the outside of the carb but nothing on the inside (that I'm aware of).

Most the time a twist of the distributor can slide you through a test, but having readings are very important to see which may need a tweaking. After you get carb fix and if it fails again, be sure to grab the paperwork.

Welcome to the forum :)

Appreciate the feedback!

After admitting this problem may be beyond my skill-set, I took it into a local shop and they verified the carb is bad. My solution at this point is most likely leaning towards replacing the carb with the weber. My only concern (from what I gather) is that the vehicle will no longer pass emissions with the weber carb, correct? I can however register the vehicle in a different state (under my parents name) to avoid emissions. Replacing the carb with the weber seems to be the way to go at this point, please advise otherwise if you see fit?

Something strange happened on the way home from the mechanic shop though. As I mentioned earlier in this post, the cold start idle was revving extremely high (apprx. 4k rpm). While I 'somewhat' got that problem under control, on the way home from the shop the truck was running fine and then the idle shot WAY UP... I mean high. To the point where I had to shut it off because I was scared it blow. This happened immediately after accelerating the truck up to about 4K in 2nd gear. I wouldn't say I was abusing it, just accelerating quickly - as it should under normal circumstances. Now, i can't get it to stop revving up... again, VERY HIGH. Does this problem sound typical of a bad carb - or do you think I have something more to worry about?

Thanks in advance, I appreciate everyone's help!

it depends on how they do emissions in Colorado - I have had a Weber on Geronimo since 83 and I passed without a cat on the truck. I have one now because no one would put an exhaust on it without one. If they do a visual, you can route the hoses to look like they are there and functional, with them doing nothing - that is what I did. The high rpm issue is probably a stuck float or the inner seals in the carb blew out and is dumping fuel down the throat uncontrolled.

Thanks Pennyman! I might start another thread to ask if anyone else (hopefully in CO) has had any such luck passing emissions with the weber carb.

Here's my list of parts to order. If anyone sees anything I'm missing to convert over to the weber, please chime in.

1. Weber 32/36 Carb from http://www.redlineweber.com/carb-kit...hrysler-dodge/
- I'm going to call to speak to a rep directly but, any advice between the DGEV (electric choke) vs. DFEV (manual choke)?

2. Electric fuel pump
- Sounds like the Carter is loud as hell and I think it was 'originalowner' mentioned the Airtex E8004 is a much better option, thoughts?

3. Fuel Pressure Regulator - Holley 12-8004 (pressure range 1-4)
- From what I understand this is optional, but I'd like to hook up a mini gauge to this in order to see what my pressure is.

4. Block off plate - Does anyone know where I can buy one? I don't have a grinder (yet) to cut my own out of sheet metal.

Am I missing anything?? Thanks for your support!

Just ordered my new carb from redline weber. The guy I spoke to said no need to run an electric fuel pump, just a fuel press. regulator. Any input here is helpful? I'm trying to get all my parts ordered to get the new carb on this weekend.

We all have our opinions on setup and I'm not sure if the guy at redline drives a Mitsubishi truck or not, but most of us went to non-pulsating electric pump with webers, I use a regulator and gauge too. Keep it on or just under 3.5 psi on regulator.

Attachment 13041Attachment 13042

I second the electric pump over the mechanical and pressure reg - the reg will blow the pump due to back pressure, even with a feedback type reg.

Thanks for your feedback pennyman & BradMph. I'll be sure to do the electric fuel pump as well, always better to do it right the first time.

The electric pumps are noisy if you never had one before. They will start running when key is to on position as well as the start position, but not in the ACC position. I actually kind of like the sound now of the pump. Don't ask why, lol.
I added a lighted toggle switch also in the cab to turn off the pump from driver seat. If you ever park in a place that seems risky, you can flip the switch and anyone trying to take the truck will get 10 feet and kill the engine.

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Originally Posted by BradMph

The electric pumps are noisy if you never had one before. They will start running when key is to on position as well as the start position, but not in the ACC position. I actually kind of like the sound now of the pump. Don't ask why, lol.
I added a lighted toggle switch also in the cab to turn off the pump from driver seat. If you ever park in a place that seems risky, you can flip the switch and anyone trying to take the truck will get 10 feet and kill the engine.

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Yeah, I had a walbro fuel pump in a civic back in the day that was pretty loud as well. However, I read that 'originalowner' recently changed out his Carter (he said it also quit working after 6 months) for an Airtex, and it's much quieter. Not sure which one to go with?

Also, can anyone provide me a link to purchase the block off plate needed when converting to electric fuel pump? I know someone mentioned these being all over the internet, I just want to make sure I get the right one.

Many thanks!

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Originally Posted by Ramshorn

Yeah, I had a walbro fuel pump in a civic back in the day that was pretty loud as well. However, I read that 'originalowner' recently changed out his Carter (he said it also quit working after 6 months) for an Airtex, and it's much quieter. Not sure which one to go with?

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I went with the Carter because of what I read here a year ago.

Everything I post here is backed up with my own real world experience. The Carter only lasted 8 months. I'll be damn if I was about to put another one on. With such an accelerated failure I was not about to take the chance.

I am on disability due to multiple strokes, do not even drive 5000 miles a year, barely a tank of gas a month.

The Carter cost me about $65 bucks plus $10.00 shipping. The Airtex E8004 that I put on to replace it cost me $110.00 at CarQuest. It can be had for about $70.00 bucks plus shipping from Amazon. It is noticeably quieter than the Carter, it just gives off a fairly quiet "hum" not very noticeable at all really. The Carter sounded like a three cylinder thrashing machine. Plus it failed at just over 6 months. No thanks on another one. Maybe I just got a bad one. Maybe, maybe not. All I know is that it failed and left me on the side of the road when it was 90+ out 8 months after I installed it.

I really don't know why my postings are treated like I am a pariah here. Not in the clique I guess. From day one I have been polite and respectful, but I admit to being quite blunt. I just tell it like it is with no sugarcoating.

I have real world experience that includes 20 years of writing service at dealers for 17 different makes...high line European, domestic, and Asian. I watched ASE Master Mechanics work at all those dealers and am not interested in doing anything half-assed.

Your money your truck your choice but I doubt I would choose a Carter if you gave me one. Unless I could keep a spare in the truck. And if you do, are you saving any money?

Sorry for coming off as what appears to be arrogant. I just tell it like it is. But I also took the time to post pictures with detailed descriptions to help others in the 2nd Gen electric pump install thread.

/rant over.

I think you did a great job with the details of installing the pump on the 2nd gen - I have not seen your responses as being harsh, just honest. Keep on posting!

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Originally Posted by originalowner

Sorry for coming off as what appears to be arrogant. I just tell it like it is. But I also took the time to post pictures with detailed descriptions to help others in the 2nd Gen electric pump install thread.

/rant over.

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Hey originalowner - Sorry for the misunderstanding - I really value your opinion and insight and don't think of you as arrogant at all.

This truck is less than a month old to me, and I'm only asking for opinions here bc from what I've read, you all seem to be very knowledgeable! The post you wrote about the 2nd Gen electric fuel pump install was very informative with great pics - I'm sure I'll have it open when installing the new fuel pump.

Thanks for all the support, keep it up!

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Originally Posted by originalowner

I really don't know why my postings are treated like I am a pariah here. Not in the clique I guess. From day one I have been polite and respectful, but I admit to being quite blunt. I just tell it like it is with no sugarcoating.
.

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I haven't seen this happening here with your posting. If I do, I will be more then happy to step in and correct it, since it seems to annoy you so much.
Also sorry your Carter fuel pump didn't work out for your truck. Perhaps it was just a failure of the product, not really sure. Mine has been right on the money for almost a year, but I run a regulator and gauge with it and not sure if that has prevented a problem either. Sometimes things happen, just like our trucks. Some trucks crack heads, some don't. Like my late father-law told me one time about vehicles. They are just a piece of metal and that's what they will always be.

Well, hope things go better for you and if you have problem with the forum, let us know for crying out loud so we can correct it. I'm sure no one here has tried to be disrespectful purposely. If they do, we take them out back and beat them with rubber hoses.

Hang in there. ;)

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Originally Posted by Ramshorn

Also, can anyone provide me a link to purchase the block off plate needed when converting to electric fuel pump? I know someone mentioned these being all over the internet, I just want to make sure I get the right one.

Many thanks!

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I think Ragtime had some a while back. I used one of them block off plates that are hanging on Oriellys American Motors Chrome parts wall. It was $10 and I had to do some grinding on it and drill out the holes a little bigger, but the piece is real thick and keeps that area from leaking oil nicely. I used some silicone on the gasket when installing.

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Originally Posted by BradMph

I think Ragtime had some a while back. I used one of them block off plates that are hanging on Oriellys American Motors Chrome parts wall. It was $10 and I had to do some grinding on it and drill out the holes a little bigger, but the piece is real thick and keeps that area from leaking oil nicely. I used some silicone on the gasket when installing.

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Thanks! It appears that Ragtime is sold out but, I found the part you used at a few national parts stores around me in Denver.

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Originally Posted by pennyman1

I think you did a great job with the details of installing the pump on the 2nd gen - I have not seen your responses as being harsh, just honest. Keep on posting!

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It's the Chicago native in me. ;)

I know that I can come across as a know-it-all when it comes to cars. I can't help that. There is not much I haven't seen when it comes to servicing cars.

No I have never worked as a mechanic, but I was ASE certified as an Automotive Service Consultant, Jaguar Service Guild member and Toyota Master Advisor. My general automotive knowledge is vast. Buying, selling servicing. All things cars. I have gasoline running through my veins.

That said, I am not the typical user here. The 70s through late 80s Jap imports are just freaks of durabilty if they are maintained properly. That's all I do with my truck, I just maintain it. And pretty anally, I might add. And because it was the first and only vehicle I bought new, I have no desire to chop it up. It's probably the most well documented MM on the planet.

No Brad, I don't have a problem here. To the contrary. My feelings are that this forum and the group on FB are fairly typical for the automotive servicing public. (Less here than FB I will say that.) Most "advice" is to throw out automotive mechanical terms which results in throwing unneeded parts at a car in the hopes of fixing it. More often than not, it's just a waste of time and money where the problem does not get fixed.

Some time ago someone started a thread where they outlined an overheating problem. I knew immediately what his problem was. Instead, he was advised to replace the water pump, thermostat, etc. All that was needed was to take the radiator out and take it to a radiator shop and have the tubes cleaned out. They run rods through the tubes to clean them out. No amount of flushing with a garden hose is going to clean those tubes sufficiently to correct the lack of circulation. You will see water movement at the top of the radiator, but at the bottom where you can't see the water it is not moving. Because the crud settles to the bottom. But it appears that the radiator is not the problem because it "isn't leaking." Not so. It IS the problem. How do I know this? 20 years of writing service at the dealership level, that's how. ;)

I don't write this stuff to blow my own horn. Rather, it is to give sound advice that will likely save someone time and money.

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