Chugging, hard start, dies on acceleration... you tell me.

Back again to boggart you guys again for information. Please be gentle, I'm still new at this.

First a tad bit of history on what is going on...

I had the hot start issue confirmed by myself and a friend that the fuel system was not holding pressure and due to my limited resources, I decided to replace the accumulator and check valve. At that point I had already received an accumulator and had the check valve on order (2-ish weeks until delivery - go figure) so I prompted to put the new accumulator in. Other than the R&R being a total pain in the butt, it went in without anything breaking. Since I have driven the vehicle many many times without issue since I picked it up, and after I replace the accumulator, I figured there would be no problem taking it down to the local good guys car show - a solid 75 mile drive in one direction. She started up and drove great all the way to my parents' place then great all the way to the car show. Bear in mind this was all in about 85° - 90° heat.

We parked the car and went the the show, great show really, lots of cool stuff. Almost too much to see with some 2500 cars there, but I digress...

We decided to leave about 4 hours later and came out to the DMC and she had a VERY hard time starting. Like I've never had a "cold" start be so hard to start. We had to do the plug swap method just to get it started cold - I couldn't believe it. Then it got really good. Driving out of the parking lot (engine appeared to be idling fine, minor accelerations were ok) and onto the road, I attempted to accelerate and it just falls flat on its face. There was nothing, nothing at all. I gave it gas and it started chugging like it was going to die, almost like it was getting no fuel. It would idle into gear but would do nothing but chug and sputter under load.

Long story somewhat less long, had to have it towed to my parents' place up the road. A week later I received the check valve (unrelated I'm sure) and a new fuel filter. Replaced the pair of them and low and behold, she ran and accelerated - still had a very hard start, had to do the plug swap. The next day... nothing, again. At about 15% throttle or less it will rev, but anything above that and it just chugs and sputters until it dies - hot or cold. It seemed to have happened all of the sudden and, suspiciously, it happened while my car was sitting at the car show. I had figured a clogged fuel filter was the culprit here or possible faulty accumulator, but now I'm not sure where to start. I also checked the plug wires and coil wiring for possible faults and found nothing.

Anyone have any ideas?
Thanks, again, in advance.

First thing to check is the fuel mixture. Maybe your prevous owner adjusted it with the bad accumulator and plugged fuel filter. Now that those are fixed the mixture may be off. Don't know why it would drive that 75 miles fine and then act up after that.

Check for vacuum leaks. That's all I got to start.....

Did you run it low on fuel? Do you know if the tank was thoroughly cleaned out? I’m wondering if something got up in there.

I thought about the fuel mixture being off but that wouldn't explain why it acted up out of the blue. I know there is a minor vacuum leak and the only thing I can think of regarding a leak is that something got sucked in. I believe the tank has not been cleaned out, but due to a partially faulty fuel gauge, I always fill it up before I go anywhere.

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Originally Posted by LoveThySpatula

I thought about the fuel mixture being off but that wouldn't explain why it acted up out of the blue. I know there is a minor vacuum leak and the only thing I can think of regarding a leak is that something got sucked in. I believe the tank has not been cleaned out, but due to a partially faulty fuel gauge, I always fill it up before I go anywhere.

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It's pretty easy to pull the fuel pump and have a look at the screen and see if it looks bad. Also, you can disconnect the output hose and run a temp fuel hose into a 5 gallon bucket and jump the RPM relay, get that fuel pump running and see what the flow looks like.

RPM jumper for fuel pump: http://dmctalk.org/showthread.php?11...-the-RPM-Relay

Sounds like you may have a few unrelated issues going on simultaneously.

First thing's first - you need to determine if you truly have a cold start problem or if it's actually a hot start problem.

In hot sunny weather, hot start problems can be prevalent even after rest/off periods upwards of 5+ hours - especially if the car is parked in the sun the entire time on a hot surface, such as asphalt, blacktop, etc.

If you can't get the car to start from cold (and you're certain it's cold and not hot) without doing the plug swap trick, then it suggests either a faulty or unplugged TTS (thermotime switch) or there's a problem with the 12V feed on the CSV's plug. If you're sure that you're having a true cold start problem, then you'll have to test the 12V feed on the CSV's plug and if that's good, then you know that you have a bad or unplugged TTS, and it will need to be replaced. If you're not getting 12V on the plug's feed while engaging the starter, then you'll need to determine why and remedy the situation that's preventing such.

As to your running problem, check to make sure that all your vacuum lines are secure and aren't leaking. Check the air induction system for any leaks by using targeted sprays of carb/throttle body cleaner while the engine is running. Also spray around the lower half of the mixture unit (by the idle air motor's intake tube - aka the pipe of agony). If you find nothing, check the operation of vacuum systems affecting fuel and spark - namely the WUR/CPR and the electrical distributor's vacuum advance for proper operation.

It works like this:

When you first start the engine cold, vacuum from the multi-port switch in the y-pipe (under the intake) is directed to the warm-up regulator / control pressure regulator (WUR/CPR). Once the running temperature reaches 104F, the multi-port switch redirects the vacuum to the solenoid hanging off the mixture unit behind the fuel distributor. When the engine is idling, the idle micro-switch is activated (closed) and instructs the solenoid to hold the vacuum there within the solenoid. When the the engine is under throttle, the idle micro-switch is disengaged (open) and causes the solenoid to actuate and release the vacuum being held there onward to the distributor in order to cause the vacuum advance of the timing.

To confirm operation, you simply pull the vacuum lines off the WUR/CPR and the electrical distributor's vacuum chamber and/or vacuum solenoid and check for the presence/absence of vacuum during the various stages of engine operation.

If you find nothing wrong, we'll continue to diagnose and eventually get it figured out :thumbup:

Just to add to the comment about easily/quickly checking the suction side of the fuel pump... your pick-up hose might have gotten pinched or collapsed for one reason or another and the pump can't suck up enough fuel to run the engine properly. Sort of like sucking through a straw too strong and it flattens. Our cars came with a fuel warming feature... ya know, cause fuel has such a high freezing point and all. The pick-up hose might have gotten hot enough to squish itself flat or if you had already been in there and moved the fuel pump in some manner, when you reinstalled, it might have now put the pick-up hose bent up against the side or bottom of the tank. Worth a check anyway.

All good suggestions. It also reminded me of one fault I had. I was running "John's" power pump which has a smaller dia. than the stock pump. So the pump had a foam spacer to hold it in the bracket. Well that foam spacer failed and let the pump twist. It tore my pickup hose so the engine stopped but I could see it just twisting the hose so you would get very limited fuel flow.

Since your problem happened suddenly, I'm thinking like the others that your problem may be in the tank.

Quote:

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Originally Posted by Bitsyncmaster

All good suggestions. It also reminded me of one fault I had. I was running "John's" power pump which has a smaller dia. than the stock pump. So the pump had a foam spacer to hold it in the bracket. Well that foam spacer failed and let the pump twist. It tore my pickup hose so the engine stopped but I could see it just twisting the hose so you would get very limited fuel flow.

Since your problem happened suddenly, I'm thinking like the others that your problem may be in the tank.

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Check the pick-up hose in the tank and make sure the frequency valve is buzzing. Tale the plug off and put it back on a couple of times.