94 Vitara surging? timing?

[Deadduck]

I have a 94 Vitara g16b engine manual 16 valve when I am driving it drives fine but in second and 3rd it is the most noticeable when I put my foot down it is slow (feels like timing is being retarted) then as the RPM hits about 2500-3000 it then all of a sudden kicks in (like timing has come back) revs faster and takes off. What could be cause of this.
I have aftermarket coby (New Zealand) free flow extractors 4-1. have changed O2 sensor (not with new one but have tested one in there on scope and seems to be fine). I have set base timing with terminals connected I have put on 12 degrees but running higher octane gas have run it like that for a while never used to do it.

[fixkick]

ENGINE BOG: (no scan tools)
is compression 170+ PSI all 4, WOT? (check off good engine) )sea-level and heads not milled deep. (stock compression)
"lack of power from the engine. but has full power WOT."
and it's not misfiring. (felt) Misfiring is felt and heard, it's violent , and is not bogging, clean bogging is LEAN AFR.
is CEL lamp OUT running (but glows key on?)?

The EGR is dead now (cat gone). so you'd get code 51s all the time, (if in fact it has and EGR, some dont, some JDM cars some are EGR free and 02 free, new)
my guess is this is the Pacific market, car. with fire wall tag marked 27(NZ) or 24 right hand drive? RHD?
see code 01 here, http://www.fixkick.com/specs/Body-TAGS/i...%20tag.jpg
what is your 01 code.?

i bet if you gun the throttle by hand (timing light attached) the advance works perfect , the ECU cant help itself advance works all the time , unless you have it slammed in to limphome mode (suz failsafe) (driver with the diagnostic jumper inserted and see if code 12 changes to other codes as power drops (bogs)?

the 02, goes off line when you accelerate or go WOT, so its not the O2,
if not misfiring , or plugs turning black (tips checked)
then its lack of fuel. if lack of fuel then that has like 3 causes.

1: low fuel pressure. (filter clogged>):?
2: injector clogged, seems not if the WOT power is good. (WOT=wide open throttle)
3: ECU doing that, but why.??? (lean deal)

ill pretend spark and engine are good and guess 3
if its only #3 then its inputs to ECU are wrong, (its not the 02) its the MAF weak or dirty but then why would WOT work good (full power) so i land on TPS.

THE TPS gives all early TIP-IN power (right throttle foot) The TPS action causes the ECU to go to ACCEL mode, enrich mode about 12:1 AFR (air fuel ratio) goes richer, if not it bogs, and then catches up. (how fast is catches is a prime clue , only the driver can witness)
does yours catch up.? fast, or does only WOT (right foot action) return power.
if the fast catchup (small seconds) don't happen the fuel pressure is low.

side topic:
i'd not run 12degr. static advance. Hi Octane is a waste if , not using higher compression head, you do know low octane fuel burns faster than high , right?
this engine has no anti-knock sensor, so zero protection, if you cause Detonation. (boom)
at idle the ecu uses spark adv. to hold idle speed perfect, fine tuned, and running 12deg. can mess that all up. (leaving only the ISC slow actions to control idle (sluggish)

recap.
id need more information on how power on demand behaves....
when you accelerate the 02 turns off. (by design, hard coded too.)
the TPS is the first signal to the ECU that the driver needs ENRICH mode ,NOW. (it's fast as lightning normally) and does and driver feels full power now....
the MAF is a slow device, and reports too late , thus the above rule. (if the maf is bad power felt ,acts backwards)
If the TPS is dead , the engine BOGS fast as lightning. very fast BOG.
The MAF wakes up in 1second and all is good.

if we had a scan tool all this can be seen LIVE.
but we dont.
ON a car with scanner we can see all sensor work great
so the fuel pressure must be wrong.

now the FPR part.
it can fail like 5 ways, but 1: good, 2. stuck open and 3: stuck closed,
The MPR on this engine, raised pressure about 6psi when you stomp you right foot,if it fails to do that, the engine will bog, and most of these cars now, all have bad FPR.
they dont last 21 years.mostly dont.

the fuel pump pressure tests , include this device, I do 3 tests for it, (key on, idle , and wot)
and the injector balance test.


Id drive with the jumper planted , sure would.
all years covered. on DLC (lots of photos)

http://www.fixkick.com/CEL/DLC/DiagJump.html

[fixkick]

got full power up a tall hill????????????
just one question. and is very important to know....

---

CEL lamp one key on?
then start engine and the CEL goes out.
this is for all cars made 88 to now with OBD EFI systems.

[Deadduck]

compression is good 170 cylinders leak down test 1-5% all ok only has a slight miss at idle or when i get water over dizzy cap or ignition parts CEL is off comes on key on engine off so fine no cat been gone for a while now never had this problem till now code is 24. I will check fuel have not done that yet but its only in certin RPM ranges and it is constant everytime it does it. as i got reading down WOT is the problem that is where it does it. When I put my foot down it is bogging until I hit 2500-3000RPM not set time but more like a set rpm. notiiclble most on hill I wanted to pass/ speed up so change from 4th to 3rd and WOT bogs till i hit 2500-3000RPM every gear.

I Will do some more tests
thanks

[fixkick]

ok all codes, not 51 are serious.
51 is egr sick, no big deal.
but 24 , never lies. its a hard failure. or is this the body tag code 24 or australia.
VSS Vehicle Speed sensor failure , but i dont think it causes hard bogging like that. only minor loss of power.
but on some FSM the VSS dead is listed as a failsafe (limphome ) activation.
my guess is 2 problems at once, the VSS in the speedometer is dead, is the speedo still working and odometer? one of the 2 must work. or Vss will be dead.

so for now.
vss dead for sure. (seem its not a DTC code but 24 is the market code...) so i put this here from confused. i am.
TPS , suspect
fuel pressure is always suspect in power issues.
MAF, is easy to test. 3 voltage out, keyon, idle , and gunned throttle , voltage out.

on a good ignition system you can spray a fine mist of water on those parts and it will not misfire, the insulation stops this.
(no drowning it in water, just mist)

great the engine is good, no cat to melt
so is just spark and fueling.
if spark parts are all new, then just fueling now. (i recommend those bosch mag wires, for max life and best HV power to the plugs)

[Deadduck]

Has new bosh leads cap and rotor on the way but were new 6 months ago body tag code is 24 and maf isnt even 8 months old i bought a new genuine one little while back going to change the fuel filter when i put the new gas tank in im gunna say fuel filter has never been done in its 275000kms but you never know all the diffs and gearbox had new oil in when i got it so maybe it has but ill do it any way. just trying to sort out fuel pressure gauge now to test fuel pressure

[fixkick]

surging has 2 causes.
1: lean air fuel ratio
2: ISC is doing it.
The ISC can even amplify the lean surge, UGH!
the ISC can also fail to release as you step on throttle and even fight your right foot, surging, as you tip-in, if the TPS idle calibration is wrong and releases too late.
if engine has full power ,im sure the new MAF is ok.... sure it is... and very expensive.
market 24 car, that is good to know buying parts !

tps bad or set wrong.
or fuel pressure bad,, how is full throttle power? up hills. if weak , low fuel pressure if not gross misfiring.

im sure its a simple problem.
the filters clogged will cause the rear nipple test port to read 60PSI (wrong and shunted) at the filter 6mm banjo test port.
i just did one that read, 55, this caused low rail pressure.
it is a full flow filter so. must never be allowed to clogg.

once the filter is changed you will get 3 pressures good , rail or filter port
keyon 40s
start idle 30s
and then wide open throttle it will bounce near 40s.
this shows FPR as happy and good.

[Deadduck]

I found a big problem that might be causing alot of my issues...
I had a blown head gasket so pulled off head to fix and found I bent a conrod on #4 cylinder its down 1-2mm I will redo full engine at a later date but yea luckily head was checked and turned out good