VSS code 24 questiions

[Revdogboy]

Hi All;
I have a 94, 16v, mfi, 5 speed Geo Tracker that was running fine untill the speedo died (along with the odometer/tripmeter). I could hear some noise behind the speedometer like the cable came loose and the CEL automatically came on. The car contunued to run fine so I did'nt worry to much about fixing it right away. over a months time it started running a little rough (harder to start and bogging under load) so I tuned it up cap rotor, plugs, wires (the $95 dollor ones), air filter, oil.
The car still bogged and kept getting worse. After reading many posts here I think its just the VSS (code 24) sending the wrong signals about fuel mixture. I've had the instrument cluster out several times trying to figure out if its the cable itself (it looks fine) or the speedometer itself or the VSS sensor (do you have a picture of it?) I did pull the dome light fuse just to see if perhaps I could get a different code... still only 24. Anyway, whats my best course of action and does it make sence that all the trouble is the VSS? Thanks

[Rhinoman]

The VSS is a reed switch on the back of the speedo head. There are two wires that come off the flexi-circuit, usually one is yellow. The VSS isn't integral to the speedo so I would suspect that your problem is the cable. I wouldn't expect it to have too much of an effect on the running of the vehicle. Its usually used for fuelling corrections on decelleration.

[jtgh]

rhinoman is correct.
and there is a Oxy sensor monitor that watches deAccel and may throw a bad oxy if VSS is bad. ( i stumbled on in playing with my 91 ecu)

get a new cable or a used speedo head from a wrecker, dont even ask for new price.(on head)
you will be shocked.

[jtgh]

if forgot to say most head parts are also available in sub component parts.
some have 3 or 4 subassemblies with Suz pn on each.
can be purchased. if for example 1 gauge fails.

cheers.

[Revdogboy]

Do I need to fix the speedo problem before working on the bogging problem? (having troube locating a used speedo unit here in San Diego).

It takes 5-6 turns of the key to get her to start up. No foot on gas works best... maybe 3-4th turn just a little feather on the gas helps.

Once started it idles fine. When cold it boggs when revving the engine. when warm it rev's up fine.

When warm it also drives fine on flat ground if I only slightly press on the gas. If I gas it (push hard on the gas) it boggs... so, as you can imagine going uphill is tricky.

all my air intake hoses look clean and intact but I may just start replacing the vaccume hoses just because (maybe I'll find something along the way)

I did notice that I have a little oil seepage around the valve cover (EGR) valve (the one located on the front left of the cover that goes onto the intake manafold) also I think I 'm developing a little oil pan leak around the gasket on the front of the oil pan (crank case pressure problems???)

Anyway, I'll be digging around today and just wanted to thank you guys for your awsome help.

THANKX

[jtgh]

classic lean problem.
but it can be many reasons.
bad fuel pump (very weak)
stuck open Fuel pressure regulator (rap it with the back side of a screw driver might unstick it for 1 day or so)

gross induction leak, ( vacuum leak)
or a bad MAF.

since it fails (bogs) hot and cold , i must presume the engine gets hot and ECT is reflecting that heat to the ECU. (ect is electronic water temperature)

I'd first measure fuel pressure.
The ECU is programmed to expect this to be perfect, if not , mixtures will be bad.
my PUmp page shows the hard data on that.
click below sig. click pump link.

the adaptor for measuring fuel pressure is $10 see link to supplier.
on a the 16v one needs an adaptor .

some here ( not me) pinch the return line for a second or 2 and see if power returns.
if yes, pump pressure is bad.

pinching the return line , puts heavy stress on the pump (shunt test) and must not be done more than say 10 seconds.
however getting to the return line under the intake man is hard.

Fuel-pump-testing

see tool 2267 link.

btw: many kicks have a rusted fuel pump ground wire behind the Left rear tail light.
id make the baby clean and shinny and the grease it.
can cause dead pump, weak pump and intermittant pump.
easy to inspect too.
see wire lug at 2pm attached to body there.
cheers