engine problem

[sirrocket]

I have a 94 that I bought 2 years ago for a grand, but it didnt run right replaced coil pac new plugs and wires and it drove fine for a bit but then it started haveing some hesitation and the tach dropped to 0 and check engine light would go on, this got progressivly worse. Reading here it sounded like the crank position sensor might be bad so I replaced waterpump, replaced crank position senser and seals and one motor mount. It ran great for a day or two then I started to feel hesitation occasionally and the check engine light came on tach drops off again and the check engine light comes on. But it doesnt last turn it of and back on and everything cleared and drives fine. this slowly got worse and worse I managed to finally have a bad code as I passed a autopart store and stopped to check the codes left it running brought the code reader out had to turn it off for the reader to read the codes and when it came back on again the check engine light was clear. There were no codes to pull. around this time I started to hear a whining from the back thought at first it might be the radio picking up interference but it did get louder and seemed to pulse with the rough running engine. would a bad fuel pump or perhaps one that got clogged cause this? Could it be something else?

 

[tery]

have you changed the fuel filter?? I bought four older Shos this year and they all had badly clogged fuel filters, and on one it contributed to killing the fuel pump. When I took off the old ones, I had to blow like blowing in a trumpet to move air through it, Im surprised they would get any fuel at all...and I never got any codes from that issue either.
Good luck. I'm still very new at it all, but you'll find great people and great help on this forum!!
Do a search for reading codes on this forum, it's very easy to get them to read out from the cel, and many people here can tell you the meaning of the codes from memory,
T

 

[sperold]

There will be codes (stored) so try the 2 tests again. Usually, if the light comes on, a code is sent and stored, even if the light goes back off.

Anything to do with the tach suggests the camshaft position sensor, but often it has a companion problem where it takes a few tries to get it started. It usually sends a code.

You can test the fuel pressure on your fuel rail on the motor and the point of connection looks like a tire valve, so try that, something in the 30s is good.

You will hear the fuel pump when you first turn the key to "on" (for a few seconds) and that is as loud as it gets, so check that out.

We need more info like Auto / Manual, and when you did the wires refer to this diagram only:
http://www.shoforum.com/showthread.php?t=89091

 

[Toolman]

Double the cam-sensor idea

 

[rubydist]

tach dropping to 0 randomly and random poor running will be a cam sensor 90 out of 100 times. The other 10 times it will be a connector or wiring issue to the cam sensor.

 

[sirrocket]

It is a MTX I did the wores and coil pack about 2 years ago the Cam position sensor and water pump and gaskets about a year ago. Changed fuel filters then have tried a couple of times to get a code but every time nothing comes up no codes at all. The fuel pump does make a whine when started when the car starts to stutter and not run right the I'm guessing fuel pump starts whining in sinc with the stuttering. I did buy a new fuel pump, any recomandations on taking out tank and cleaning it?

 

[sperold]

You will not need to clean the tank, so I would leave that alone.

You could get a new fuel filter if you are concerned about fuel. It is on the passenger side under the rear door where the lines go straight up into the tank. They have some clips that you have to remove with a small screwdriver and small long nosed pliers. Wix are $4.00 and Fram are $10.00.

I see now that you already bought the fuel pump. On mine, I removed the straps and pulled the tank down and changed the pump on the floor in front of me. The ring that you have to tap off requires a lot of tapping and moving with a screwdriver, when you live in my climate. Buy a new ring and gasket for the tank and consider new straps.

Putting the tank back in is fairly hard and you should use a floor jack with a board on it. If you find the studs are too short where you put the straps on, it means the tank is not up in its final location yet, and it requires a lot of wiggling to get it "home".

Consider doing the floor cut (see topics on it) while the tank is out as it is easier, there in no chance you will cut the lines, and you can check on the connections after it is installed. Also you can reinforce the area around the hole to put back some strength, which is something you cannot do with the gas tank (and gas) in there.
In my area, there is no reason to do the access hole as the fuel pump outlasts the tank, but where you are, it will be the other way around.

All this fuel system stuff is nice, but your real task is changing the cam sensor.

Do the cam sensor first and get it running well. The MTX is slightly harder to put a cam sensor in as it has a little less room. Most people pull the wheel and inner fender. Buy a good one as it is not so easy to change.

 

[sirrocket]

You will not need to clean the tank, so I would leave that alone.

You could get a new fuel filter if you are concerned about fuel. It is on the passenger side under the rear door where the lines go straight up into the tank. They have some clips that you have to remove with a small screwdriver and small long nosed pliers. Wix are $4.00 and Fram are $10.00.

I see now that you already bought the fuel pump. On mine, I removed the straps and pulled the tank down and changed the pump on the floor in front of me. The ring that you have to tap off requires a lot of tapping and moving with a screwdriver, when you live in my climate. Buy a new ring and gasket for the tank and consider new straps.

Putting the tank back in is fairly hard and you should use a floor jack with a board on it. If you find the studs are too short where you put the straps on, it means the tank is not up in its final location yet, and it requires a lot of wiggling to get it "home".

Consider doing the floor cut (see topics on it) while the tank is out as it is easier, there in no chance you will cut the lines, and you can check on the connections after it is installed. Also you can reinforce the area around the hole to put back some strength, which is something you cannot do with the gas tank (and gas) in there.
In my area, there is no reason to do the access hole as the fuel pump outlasts the tank, but where you are, it will be the other way around.

All this fuel system stuff is nice, but your real task is changing the cam sensor.

Do the cam sensor first and get it running well. The MTX is slightly harder to put a cam sensor in as it has a little less room. Most people pull the wheel and inner fender. Buy a good one as it is not so easy to change.

So the Crank position sensor is different then the cam position sensor?I thought t was the Crank position sensor that gave the data for the Tach.

 

[tery]

if your crank sensor was the problem, the car wouldn't run at all, or if it did, it wouldn't be long before it wouldn't run at all, When the crank sensor is gone, you get no spark, period
At least that is my understanding at this point from reading posts, It would behoove you to search all these terms and threads in the forum here, there is just about everything you want to know or can think of to ask, ya just have to search, I've been learning that over the past months, AND the people here are a great help

 

[sperold]

You are not the only one to think that the cam sensor runs everything, but it is not true.

The tachometer gets all its information from the cam sensor, while the engine management system gets all its information from the crank sensor and uses some cam sensor info to back up the core data. Your intermittent issues are caused by the engine management system believing the cam sensor information occasionally.

My wife has a Suzuki, and all the data to run everything comes from the cam sensor and it uses the crank position sensor to back up the cam data. With it, you can have a crank sensor code and the engine runs and starts perfectly. Completely opposite the SHO.

 

[tery]

the other thing that could be involved is the crm, control module relay, it is a black box under the far right side of the plastic radiator shroud and can cause all kinds of problems, like the some of what you've described. I've had to replace 3 in four cars that are all gen 2 as well

 

[tery]

thanks, see I too you, people here are great teachers~!!