[tuolumne]

I think I may have a debilitating emissions issue. We broke down Saturday...vehicle will idle fine, but cannot rev up at all. If vehicle is cold, it has power (not great, but can accelerate) during open loop time, but will not accelerate after warmed up.

Background: Friday I replaced a broken thermostat (had been open all winter), changed the fuel filter, and installed new plugs and wires. The van ran great for the first hour, then got steadily worse for another hour until it had no power at all. It was a warm day, and the first time in a while that it has run at the correct operating temperature. Could something (buildup from previous cold operating temps) have broken loose and clogged the EGR, catalytic converter etc.? I have a permanent engine code, but no reader to get it. The vehicle will rev. when cold, so does that eliminate the catalytic converter? The vehicle will not rev in park or neutral when warmed up...does that eliminate the EGR valve? I am not a very knowlegeable mechanic, please help.

 

[toddb]

prolly a bad sensor. doesn't sound to serious to me.

Wait until you get a reply from some of the experts on here.

 

[Mr_Bowtie]

First go find out what the SES light is saying to you. Autozone can check the codes for free.

Do you smell gas or anything black crap out of the tailpipe? I would almost think since you changed the plugs and it ran good for a while that the old ones were fouled out(how do the old plugs look?) and now the new ones fouled out on you. Like your running too rich. My Van is currently taken apart cause the fuel pressure regulator and fuel rail inside the plenum are leaking fuel causing it to run super rich. OR your 02 sensor might not be cycling like it should(bad wire to 02 sensor or bad sensor) causing the motor to run super rich and foul your plugs in short order.
But, if your not smelling any fuel out the tailpipe then its probably not the case.

My experience with clogged cats is that the car will run fine, but won't get over a certain MPH. Never caused a un-ability to rev in park. At least thats my personal experience with them. :banghead:

 

[tuolumne]

I cannot take to Autozone since the van is not driveable (that sounds serious to me by the way!). Until I can find a reader to borrow the codes will remain a mystery.

The old spark plugs were the original 100k platinums at 112k...they looked worn out, but not fouled. I did not change them for any other reason than it seemed to be time.

 

[Mr_Bowtie]

Well a cheap code reader from Wal-Mart would be really handy right now. I want to say they are about $40. Not cheap to me, but they are cheap compared to some code readers and it should point you in the right direction.

How does the exhaust sound? Normal? Choppy? Spitting any fluid out of it? Smoke?

I wish I could be more help. :banghead:

 

[toddb]

I cannot take to Autozone since the van is not driveable (that sounds serious to me by the way!).

Yes, I agree, but I meant it should not be too expensive to repair.

 

[Matrixx]

Hi tuolumne

I have to agree, If you can possibly get that code read, it should steer you in the right direction.

-When did this problem occur? (before or after the plug change)?
-When was the last time you had a "complete" tune-up done on it?
-When was the last time you replaced your fuel filter?

Thanks.

 

[tuolumne]

I've read the codes stored in the OBD. Only two exist; one is manufacturer specific code for fuel gage malfunction...the fuel gage has not worked for years, so no suprise there. The other code is P1870 - transmission slipping. Does this make any sense? It does not seem to fit the behavior that the vehicle exhibits.

 

[timelessbeing]

Maybe torque convertor isn't locking up. Is the tranny fluid up full?

 

[tuolumne]

The transmission fluid level is good, it looks and smells fine. I changed the fluid around 25,000 miles ago. My question is, could the tranny affect engine behavior even when in neutral or park...would engine be bogging down like this etc. Also, I would think that the miles I drove at 10 mph would have created a real stink if something was slipping. Our van has done the first to second clunk when really hot occasionally for five years (60,000 miles) including our fateful trip last weekend. This has never worsened (we're gentle during its occurance) but could this be the source of that code (P1870) and unrelated to the debilitating issue?

 

[K_Shields]

How much Pressure is coming out of tail pipe? When the converter goes bad you can usuasly here air escaping Donut gasget. a Clogged converter will reduce engine Rpm and slow it down to a crawl.

 

['cudapaul]

"Our van has done the first to second clunk when really hot occasionally for five years (60,000 miles) including our fateful trip last weekend. This has never worsened (we're gentle during its occurance) but could this be the source of that code (P1870) and unrelated to the debilitating issue?"

This would have nothing to do with the lack of power. The P1870 indicates that the transmission is slipping. The engine computer, courtesy of OBD2 magic, has determined that the relative speed of the input to the transmission does not match the output, therefore it is slipping. The slipping is turned into internal heat in the trans.

The "first to second clunk" is because the computer has raised the transmission's internal hydraulic pressure to prevent or reduce damage to the trans from the slipping. When you park the van for a while (ignition off) the computer resets and allows the trans to work normally. As soon as it detects slippage, it will set the P1870 code. This usually occurs after the vehicle has warmed up and has been driven for over ten miles above 55-65 mph.

The problem is caused by wear or a manufacturing defect in the valve body of the 4L60E. It is not uncommon, and several aftermarket fixes have been created. I would strongly suggest that you have it fixed, otherwise it will eventually damage the transmission to the point where it will have to be rebuilt.

 

['cudapaul]

In thinking about your problem, you may not have enough fuel pressure. That is why it would more or less run at idle, but when more power is demanded, there isn't enough fuel to sustain it.

This could be due to a weak or worn out fuel pump, or a clogged fuel filter. You don't indicate what your total mileage is on the van, or if the pump or filter was ever replaced, but the system fuel pressure should be tested to determine if it is meeting spec.