Catalytic Converter, O2 Sensor & EGR Questions

[Von]

I have a 94 Suzuki Sidekick JLX 4x4 with a 1.6L 16v engine. The PO removed the catalytic converter for some reason and now is straight piped. I installed the Doug Thorley 4-2-1 header on the vehicle for it came with it when bought but was never installed. The header will not meet with the existing mid pipe and the flange is different. Before I cut and weld the proper flange to the mid pipe should I get a cat converter and install. I’ve heard the EGR needs the back pressure from the cat to function properly or it will throw a 51 code. Is this true for this model and if so should I put the cat back in? I have no emissions laws where I am from so this question is purely to make sure it is running properly.

Thank You

Edit: this thread started from a simple question regarding if I should re-install the catalytic converter that the PO removed prior to creating a custom exhaust setup to fit the Doug Thorley 4-2-1 headers. Prior to the header install I changed the water pump, timing belt, set the valve lash, replaced the spark plugs, all fluid, air filter, O2 sensor, and all popped or wrong amp fuses. After all this work I got the cat and installed. I went to fire it up and it would crank but not start. I was super worried for with all that work at once there could have been a number of things that could have gone wrong. I looked around the engine bay and found that the PO not only removed the cat but removed the EGR from the engine with all vacuum and wire still connected. I thought that this could be the reason why it did not start. I was re assured from kickfix that it would still start with the EGR in this state. I continued to look for issues and found that the IG Coil fuse under the dash was popping every time I tried to start the vehicle. I then disconnected the O2 sensor on a whim and the big Lexi fires right up (still with EGR disconnected). I’m now at the point where I’m trying to figure out the correlation between the O2 sensor and the IG Coil fuse.

Edit edit: I still don’t know why a bad O2 would cause the IG fuse to pop on startup but I replaced the O2 with a different one (Walker) and it fires right up. I have not lost another IG fuse to this point many miles later. Long story short, you need a functioning O2 sensor in this vehicle or you could pop an IG fuse. You should have a cat converter installed if you want to have enough back pressure to operate the EGR. Also make sure the pathways to the EGR are not clogged. As far as the Doug Thorley headers I’m not sure why they made them the way they are but they have a flange at the bottom pipe going towards the cat that has a conical gasket that looks to fit the flange for the down pipe I removed the only problem was that with the header the downpipe is basically removed entirely. The cat has a flat surface for the flange. These 2 flanges do not meet up and do not work together. The Doug Thorley header is not an exact fit bolt on header to the exhaust. What I did to fix this issue was cut the flange from the old down pipe and weld it to a new piece of pipe going to the cat. This way it fit like a conical gasket and socket flange. Also the rubberized gasket that came with the older kit melted so I got a new lead replacement Doug Thorley gasket that now come in the new kits from from trail tough my local shop. The lead has not yet melted or warped. I hope this helps someone in the future.

[fixkick]

I have a 94 Suzuki Sidekick JLX 4x4 with a 1.6L 16v engine. The PO removed the catalytic converter for some reason and now is straight piped. I installed the Doug Thorley 4-2-1 header on the vehicle for it came with it when bought but was never installed. The header will not meet with the existing mid pipe and the flange is different. Before I cut and weld the proper flange to the mid pipe should I get a cat converter and install. I’ve heard the EGR needs the back pressure from the cat to function properly or it will throw a 51 code. Is this true for this model and if so should I put the cat back in? I have no emissions laws where I am from so this question is purely to make sure it is running properly.

Thank You

yes, cat back pressure makes the EGR work. (modulate)G16 engines
but code 51 is USA cars, is yours USA?  many cars in canada (all really) have there own ECU. (market code 28 ECU = canada)
if you open the hood and look up , and under and you see the USA smog sticker there from Suzukik
in the center it tells you USA EPA regulations or California. like this.

https://fixkick.com/specs/Body-TAGS/html/image_8.html

if you see that word USA< that is  Code 51 ECU.. by law..
the other down side, of no CAT is this..
1: hot summer day and engine.
2: parked at  RED light, for 10 min and windows down,  or worse 2door car top down.
3: the stench of raw exhaust,  can be really bad. drifting from rear to front of car..

that is it on EGR,  EGR can be very hard to get working , due to carbon build up in all paths.

[Von]

I have a 94 Suzuki Sidekick JLX 4x4 with a 1.6L 16v engine. The PO removed the catalytic converter for some reason and now is straight piped. I installed the Doug Thorley 4-2-1 header on the vehicle for it came with it when bought but was never installed. The header will not meet with the existing mid pipe and the flange is different. Before I cut and weld the proper flange to the mid pipe should I get a cat converter and install. I’ve heard the EGR needs the back pressure from the cat to function properly or it will throw a 51 code. Is this true for this model and if so should I put the cat back in? I have no emissions laws where I am from so this question is purely to make sure it is running properly.

Thank You

yes, cat back pressure makes the EGR work. (modulate)G16 engines
but code 51 is USA cars, is yours USA?  many cars in canada (all really) have there own ECU. (market code 28 ECU = canada)
if you open the hood and look up , and under and you see the USA smog sticker there from Suzukik
in the center it tells you USA EPA regulations or California. like this.

https://fixkick.com/specs/Body-TAGS/html/image_8.html

if you see that word USA< that is  Code 51 ECU.. by law..
the other down side, of no CAT is this..
1: hot summer day and engine.
2: parked at  RED light, for 10 min and windows down,  or worse 2door car top down.
3: the stench of raw exhaust,  can be really bad. drifting from rear to front of car..

that is it on EGR,  EGR can be very hard to get working , due to carbon build up in all paths.

So I will be getting a Cat converter then and will have to check out my EGR for I’m almost certain it is clogged by PO not running a cat. EGRs are more expensive than I thought on these vehicles. Any helpful cleaning tips would be appreciated here. Also is it ok to install my cat right behind the Doug Thorley header or do I need some space pipe between the header and the cat? 

Thank you

[fixkick]

I have a 94 Suzuki Sidekick JLX 4x4 with a 1.6L 16v engine. The PO removed the catalytic converter for some reason and now is straight piped. I installed the Doug Thorley 4-2-1 header on the vehicle for it came with it when bought but was never installed. The header will not meet with the existing mid pipe and the flange is different. Before I cut and weld the proper flange to the mid pipe should I get a cat converter and install. I’ve heard the EGR needs the back pressure from the cat to function properly or it will throw a 51 code. Is this true for this model and if so should I put the cat back in? I have no emissions laws where I am from so this question is purely to make sure it is running properly.

Thank You

yes, cat back pressure makes the EGR work. (modulate)G16 engines
but code 51 is USA cars, is yours USA?  many cars in canada (all really) have there own ECU. (market code 28 ECU = canada)
if you open the hood and look up , and under and you see the USA smog sticker there from Suzukik
in the center it tells you USA EPA regulations or California. like this.

https://fixkick.com/specs/Body-TAGS/html/image_8.html

if you see that word USA< that is  Code 51 ECU.. by law..
the other down side, of no CAT is this..
1: hot summer day and engine.
2: parked at  RED light, for 10 min and windows down,  or worse 2door car top down.
3: the stench of raw exhaust,  can be really bad. drifting from rear to front of car..

that is it on EGR,  EGR can be very hard to get working , due to carbon build up in all paths.

So I will be getting a Cat converter then and will have to check out my EGR for I’m almost certain it is clogged by PO not running a cat. EGRs are more expensive than I thought on these vehicles. Any helpful cleaning tips would be appreciated here. Also is it ok to install my cat right behind the Doug Thorley header or do I need some space pipe between the header and the cat? 

Thank you

i cant see your header, but the right one has the #4 port EGR path, there.
the real head ache is the 4 injectors EGR in the quad port intake manifold, from H3LL.
ouch
i have no idea if other parts are missing for EGR< no photos posted.  but EGR main, EGR mod valve and EGR VSV top the list.  1994.

they also sell 94 sidekicks in the South pacific islands with no smog parts at all called JDM cars, new. then,.k
is your hood sticker missing or no funny blue aluminum placard  VIN plate just to right of  battery (facing it) or even more odd maple leaf VIn Plates in canada.
I see all this stuff in 1 second flat in person,  VIN plates missing parts,  all that.
ok what header model is it? #

[Von]

I have a 94 Suzuki Sidekick JLX 4x4 with a 1.6L 16v engine. The PO removed the catalytic converter for some reason and now is straight piped. I installed the Doug Thorley 4-2-1 header on the vehicle for it came with it when bought but was never installed. The header will not meet with the existing mid pipe and the flange is different. Before I cut and weld the proper flange to the mid pipe should I get a cat converter and install. I’ve heard the EGR needs the back pressure from the cat to function properly or it will throw a 51 code. Is this true for this model and if so should I put the cat back in? I have no emissions laws where I am from so this question is purely to make sure it is running properly.

Thank You

yes, cat back pressure makes the EGR work. (modulate)G16 engines
but code 51 is USA cars, is yours USA?  many cars in canada (all really) have there own ECU. (market code 28 ECU = canada)
if you open the hood and look up , and under and you see the USA smog sticker there from Suzukik
in the center it tells you USA EPA regulations or California. like this.

https://fixkick.com/specs/Body-TAGS/html/image_8.html

if you see that word USA< that is  Code 51 ECU.. by law..
the other down side, of no CAT is this..
1: hot summer day and engine.
2: parked at  RED light, for 10 min and windows down,  or worse 2door car top down.
3: the stench of raw exhaust,  can be really bad. drifting from rear to front of car..

that is it on EGR,  EGR can be very hard to get working , due to carbon build up in all paths.

So I will be getting a Cat converter then and will have to check out my EGR for I’m almost certain it is clogged by PO not running a cat. EGRs are more expensive than I thought on these vehicles. Any helpful cleaning tips would be appreciated here. Also is it ok to install my cat right behind the Doug Thorley header or do I need some space pipe between the header and the cat? 

Thank you

i cant see your header, but the right one has the #4 port EGR path, there.
the real head ache is the 4 injectors EGR in the quad port intake manifold, from H3LL.
ouch
i have no idea if other parts are missing for EGR< no photos posted.  but EGR main, EGR mod valve and EGR VSV top the list.  1994.

they also sell 94 sidekicks in the South pacific islands with no smog parts at all called JDM cars, new. then,.k
is your hood sticker missing or no funny blue aluminum placard  VIN plate just to right of  battery (facing it) or even more odd maple leaf VIn Plates in canada.
I see all this stuff in 1 second flat in person,  VIN plates missing parts,  all that.
ok what header model is it? #

Here are the specs to the vehicle in the attachments. Also 94 Sidekick 16v 4x4, 4dr, Hard top, 5sp M/T I’ve got the exhaust and cat converter figured out but still need EGR help. Also the blue tag is completely wiped clean and there is no text on it.

[fixkick]

tag on hood or fire wall.?   (tags are located by laws of country, USA is hood (up under) ON fire wall in other countries, not USA.
is car 4door or 2door rag top?>
94 Suzuki Sidekick JLX 4x4 with a 1.6L 16v engine. (is 4wd)
 what transmission is it, 3/4/5sp MT? that too matters. or say Auto or stick shifted,

the only other way to know what this car had, is ECU full model number. (TAG gone)
33920-58Bxx  (Xx is 10 to 90 , for different years , AT/MT and doors..  per this fine doc, I made.

The car many have EGRt sensor on the side of the EGR main valve.  this matches ECU, by year, and only the ECU part number tells what it wants.
EGR is complex, vacuum and exh, paths and VSV valve and ECU controlled. (on/off). and EGRT. (egr thermo probe sensor)
The EGR is modulated via CAT back pressure seen at the EGR mod valve on top of the engine.
The ECU runs the EGR full time but not at idle , not cold engine and not WIDE OPEN throttle (WOT)
the quad port EGR loves to clog up here.

see slide show, do not look at 1995.5 mono port , you do not have.

https://fixkick.com/sensors/EGR/90-95/SL...index.html

the 1994 should have the EGRT sensor on EGR main.
and here..
the ECU watches this sensor, and if reads wrong, CODE 51 happens, and can be cheated (ask)




Joking now...... watch out.

do not look here, this is just horror of year 1980 , to 1988 but you can see the mod valve is NOT NEW . mod used from 1980 to 1995  long run of hell.
most of these cars were crushed,.

[fixkick]

SOME of those headers made by Doug thorley are not made now (too few cars on road running I guess)
do you have this slot?


this header  has the magic hidden EGR slot..(and matching new gasket for that , calif CARB certified,  DO YOU have the slot; SOME DO NOT.

THY-716Y-C (or  THY-716Y-SS)   the SS I think is still made, for sure sold.







as you can see this 16v engine had 2 kinds of header,short and long, (calf, and fed)
long tube headers started in CALIF 1992 and later all cards when long.
ending this mess (fails hard) (had after burner plates inside the melt and block exh, flow, yah super bad.. long header is best, and not use  below #1 part

next up CALImini. 

long ago  they made these too  and are very good.

look for the tube   #4 port, seen at rear, here os CALMINI header is EGR fitted. SK703Y-S

[fixkick]

the #4 exhaust tube (shields off) will be cracked on most G16b 16v only...
then just up in the new header and drive it.
the missing crack them makes the O2 sensor work and MPG go to 26-28mpg, for sure 2door car , is it?
also the ECU is tuned for normal back pressure of CAT.. so that and EGR working....

[Von]

SOME of those headers made by Doug thorley are not made now (too few cars on road running I guess)
do you have this slot?


this header  has the magic hidden EGR slot..(and matching new gasket for that , calif CARB certified,  DO YOU have the slot; SOME DO NOT.

THY-716Y-C (or  THY-716Y-SS)   the SS I think is still made, for sure sold.







as you can see this 16v engine had 2 kinds of header,short and long, (calf, and fed)
long tube headers started in CALIF 1992 and later all cards when long.
ending this mess (fails hard) (had after burner plates inside the melt and block exh, flow, yah super bad.. long header is best, and not use  below #1 part

next up CALImini. 

long ago  they made these too  and are very good.

look for the tube   #4 port, seen at rear, here os CALMINI header is EGR fitted. SK703Y-S

My header does have that slot. Also to bring you up to speed where I am at with it now, I got the new cat. It is not melted and is installed properly now. PO removed. Prior to that I checked main cog for damage, replaced the pugs gapped .28 and wires installed properly, I replaced the timing belt but did not move the main and cam crank independently, I set valve lash to .06 but they were only off at .05 and or 0.07 so not much adjustment. The vehicle ran before but will Crank and not start now.

Assuming that all my work is correct could the new cat be the reason for it not starting. Before you answer a little back story. After vehicle would not start I started looking around the engine bay. I found the EGR disconnected from the block with all wires and hoses still connected. It seems that the PO removed the Cat and the EGR. Could the EGR being removed be the reason with the new cat that the vehicle won’t start?

[fixkick]

SOME of those headers made by Doug thorley are not made now (too few cars on road running I guess)
do you have this slot?


this header  has the magic hidden EGR slot..(and matching new gasket for that , calif CARB certified,  DO YOU have the slot; SOME DO NOT.

THY-716Y-C (or  THY-716Y-SS)   the SS I think is still made, for sure sold.







as you can see this 16v engine had 2 kinds of header,short and long, (calf, and fed)
long tube headers started in CALIF 1992 and later all cards when long.
ending this mess (fails hard) (had after burner plates inside the melt and block exh, flow, yah super bad.. long header is best, and not use  below #1 part

next up CALImini. 

long ago  they made these too  and are very good.

look for the tube   #4 port, seen at rear, here os CALMINI header is EGR fitted. SK703Y-S

My header does have that slot. Also to bring you up to speed where I am at with it now, I got the new cat. It is not melted and is installed properly now. PO removed. Prior to that I checked main cog for damage, replaced the pugs gapped .28 and wires installed properly, I replaced the timing belt but did not move the main and cam crank independently, I set valve lash to .06 but they were only off at .05 and or 0.07 so not much adjustment. The vehicle ran before but will Crank and not start now.

Assuming that all my work is correct could the new cat be the reason for it not starting. Before you answer a little back story. After vehicle would not start I started looking around the engine bay. I found the EGR disconnected from the block with all wires and hoses still connected. It seems that the PO removed the Cat and the EGR. Could the EGR being removed be the reason with the new cat that the vehicle won’t start?

THE EGR REMOVED LEAVES A HUGE HOLE IN THE INTAKE, VERY BAD THAT.
.05" is match book cover thick dont you mean .005" THICK?  or are those metric number?
IS Compression good
spark timing good
does test fuel work (sprayed by hand)'