View Full Version : Need help with 360 in RAM350 van

Ray Bell
04-28-2016, 10:24 PM
I drove this van about 14,400 miles a couple of years ago, I picked it up again a week ago and the day before yesterday I struck a problem...

After starting fine from cold in the morning I made a stop after a mile or two, the thing wouldn't start again. Bear in mind that the auto choke is always on in this thing for some reason (yeah, it chews gas), but it's never done this before.

I was, fortuitously, parked on a big hill and I rolled down that churning it over and finally it went. No further problems all day. None.

Today it started fine, I drove a mile and a half and got fuel. It wouldn't start!

In the end I wired the choke open to get it going having tried a lot of other things over an hour or more. But as soon as I started driving I got backfiring through the carby.

I drove on, this persisted, I wasn't in a position to do anything but drive (long distances between towns) and finally I pulled into a town and did the rounds of workshops who might have some carby knowledge. None can look at it for over a week!

In a week I'm due to be 1600 miles from here to catch a plane!

So I had someone suggest I look for vacuum leaks, I found one but it made precious little difference. I let the choke go on again, it still popped and banged!

I'm thinking it might be something electrical... any suggestions, I am in dire straights here in Montana and need whatever help anyone can offer.

04-28-2016, 11:55 PM
If it's popping back through the carb it's lean.

Ray Bell
04-29-2016, 01:35 AM
Any way of fixing it?

Actually, it now keeps doing it when the choke's on.

John Kunkel
04-29-2016, 03:16 PM
You didn't mention the year but 318's and 360's in some years are notorious for the exhaust crossover passage in the intake manifold plugging up with carbon, this shuts off the hot gas that makes the choke open.

The clogged crossover also shuts off the EGR (if equipped) and the manifold floor jets which causes the mixture to lean out.

Ray Bell
04-30-2016, 02:32 AM
That sounds like something difficult to fix, John...

Today I tore the carby down and cleaned it, we have very little backfiring now, but power is well off. I'm going to try richening the mixture, but the fuel usage the past two days has been horrendous.

It ran fine before with the choke closed, really it did. Went well and fuel consumption not alarming. But the problem I struck where I couldn't restart without opening the choke made it impossible to live with.

The year is '87, by the way. What are 'manifold floor jets'?

John Kunkel
04-30-2016, 02:08 PM
Floor jets are openings in the floor of the intake plenum where exhaust gas from the crossover is introduced into the intake as an addition to the EGR valve. Don't know if EGR is used on "down under" engines, very common in the U.S. starting around '73.

EGR enriches the mixture so, if the EGR isn't working, the mixture runs lean.

05-03-2016, 10:29 PM
I wouldn't think it would be EGR related. If the EGR was stuck open it wouldn't idle. If it was closed it would probably just have detonation under load. If the cross over passage was plugged it would be cold blooded but would eventually run fine warmed up.

If it ran fine with the choke on, I would be looking for a vacuum leak. Obviously it's a lean mixture issue. So either you have a fuel supply problem, vacuum leak, or jetting issue.

Take the oil cap off with it running. If it dies the intake gasket is leaking internal. Or if there is vacuum there with the PCV and breather hoses plugged.

Ray Bell
05-04-2016, 05:21 PM
It's an American engine, carburettor and van, John...

I bought it here last trip. I did 14,400 miles in it, now I've just passed another 3,000 miles this trip.

I had someone with some experience go over it today, we found some issues, but first I should say that the 'hiccupping' we had to endure for three days stopped yesterday morning, without me touching it. Though it could have been something to do with the 'in the tank' carby cleaner I put through it two days earlier.

There was some improvement in performance, but it still wasn't right and gas mileage improved from 7.5mpg to 8.1.

Today we found that the vacuum advance was sticky, the distributor was actually loose, there was three vacuum lines that were leaking.

It runs a lot better, responds better, now to check how it is on the highway and with the fuel guzzling.

Or... watch this space!

05-04-2016, 11:31 PM
What did you time the distributor to? I know factory specs are like 0 degrees. I typically go 10-12 BTDC at idle. Or 36 degrees BTDC total. If I start to get detonation then I back the timing down till it goes away.

Make sure your vacuum advance is hooked to ported vacuum.

05-05-2016, 01:27 PM
When they started riveting the electric choke housing early in the emissions era, I saw a lot of carbs that had to have the rivets drilled to make the choke adjustable, because they would close when it sat for a short while after being shut down.

Ray Bell
05-05-2016, 08:32 PM
Okay, the vacuum advance is definitely hooked up to its original position at the base of the carby next to the right hand primary choke.

No proper timing setting was done. We did some work on the sticky mechanical advance, but I'm not sure it's 'unsticky' enough yet. The vacuum advance seems okay, but no timing light was used because it's very awkward to get to it and it was raining.

Timing was set between running smoothly at idle and not making the starter beg for mercy. I don't think it's advancing enough because it's a bit dud at higher speeds.

But it is surely better at low range. Fuel consumption is no better.

Ray Bell
01-24-2017, 08:04 AM
We did eventually get this right...

Two plug leads were swapped somehow. In turn the backfiring damaged the float. I had the carby rebuilt in Indiana and the guy who did it knew it would be the plug leads swapped, he quickly found them and it was fine the rest of the trip.