Really Slow...

[gothicsera]

....truck.

My '95 350 TBI truck seems really slow - I know it's heavy and currently mostly stock but it's a lot slower than I think it should be.

Its got 3.42 rear end, stock diameter tyres.

I noticed the SES light came on last night when I was driving, then went off.

I will be giving it a good service/tune up this weekend. Unfortunately I don't have a code scanner, neither does anyone I know of in the UK.

I pulled the distributor cap and it looks pretty new inside. Rotor arm too. Plug leads also look nearly new. Air filter was good. I changed a vacuum line as it seemed a bit loose but it made no difference.

It does have headers, y-pipe with no cat and a cheap exhaust system which is all 2.5" diameter. The only O2 sensor I can see is just after the merge in the Y pipe.

This weekend I intend to do a full service and have bought:
Fuel filter
Air filter
Spark plugs, leads, distributor cap, rotor arm
TBI service/rebuild kit
New PCV valve and grommets

But is there anything specific I should look at?

 

[DerekTheGreat]

It's making a whopping 190ish HP so yeah, to push a 4x4 extended cab 4000lb+ monster down the road with 3.42's isn't going to take your breath away. I've got an '88 Long box regular cab truck with a 454, SM465 & 4.10's. It sucks too. Well when the engine is cold it seems pretty fast..

I will say though that doing these things made it more predictable & perhaps peppy:

1)Put the right plugs @ right gap & wires on it along with reman A/C Delco Dizzy
2)Set the timing to 6 degrees
3)New fuel pump
4)swapped the injectors & regulator portion of the TB for junkyard units
5)Made sure vacuum line to MAP sensor was leak free
6)Made sure the temperature sending unit was working correctly

Now it will snap your neck back but it's still not going anywhere in a hurry. My truck still has a rough idle, it sat for years so I might have some sort of valve/head issue but it doesn't set the SEL off. Going to throw a new O2 sensor at it this weekend as it runs slower when it goes into closed loop.

 

[ram1220]

Does the SES only come on when driving on the highway? My 90 did this a few years ago. I changed the EGR valve as well as the O2 sensor. It solved the SES issue as well as making the truck idle better when cold. Also made it a bit peppier.

 

[Justin S]

If you have the obd1 connector you can use a paper clip to check codes. Being a 95 I think it's obd2 though

 

[skylark]

Being a 95 you can get the codes with a paperclip. You jump across A and B of the assembly line data link under the dash. Turn the key on and count the flashes. It will flash 1 and then 1, 2. That is a code 12 to let you know that the system is functioning. It will flash the code 3x and then it will go on to the next code. If I recall correctly A and B are the ones on the top right of the connector as you look at it. Google it just to make sure.

 

[skylark]

If you have the obd1 connector you can use a paper clip to check codes. Being a 95 I think it's obd2 though

We were on the same track!

 

[gothicsera]

Thanks guys.

It's OBD1 the older square connector.

Will give it a go!

 

[jkeaton]

I take it for what it is. A big hunk of slow metal that hauls a ton of crap and does everything I ask it to do. If I want to go fast, I hop in one of my other cars.

 

[gothicsera]

It just feels slower than it should that's all. I know it's not going to be quick but at the moment it feels like with any weight behind it it'd really struggle...

I pulled the codes - but there's discrepancies with the the last 5 - some lists say transmission related, others are ignition/brake. Anyone know which is correct?

The transmission ones I am sure are a result of the problem I had with it going into limp mode due to a bad power supply to the transmission. I seem to have figured that out and reset it.

13 - Oxygen sensor open
66 -
67 -
81 -
82 -
83 -

I reset the codes and rechecked and there were no codes stored.

 

[Justin S]

O2 sensor could have an effect on performance for sure.